Merge pull request #788 from amirotin/feature/users-quota-endpoint

Add GET /v1/users/quota endpoint
2026-05-18 17:06:14 +03:00 · 2026-05-17 11:06:06 +03:00 · 2026-05-15 16:25:56 +03:00 · 2026-05-14 18:20:04 +03:00 · 2026-05-13 16:42:01 +05:00 · 2026-05-13 16:35:40 +05:00
60 changed files with 12139 additions and 5532 deletions
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -191,6 +191,11 @@ When facing a non-trivial modification, follow this sequence:
 4. **Implement**: Make the minimal, isolated change.
 5. **Verify**: Explain why the change preserves existing behavior and architectural integrity.

+When the repository contains a `PLAN.md` for the current task, maintain it as
+a working checkbox plan while implementing changes. Mark completed and partial
+items in `PLAN.md` as the code changes land, so the remaining work stays
+explicit and future passes do not waste time rediscovering status.
+
 ---

 ### 9. Context Awareness
@@ -222,10 +227,9 @@ Your response MUST consist of two sections:

 **Section 2: `## Changes`**

- For each modified or created file: the filename on a separate line in backticks, followed by the code block.
- For files **under 200 lines**: return the full file with all changes applied.
- For files **over 200 lines**: return only the changed functions/blocks with at least 3 lines of surrounding context above and below. If the user requests the full file, provide it.
- New files: full file content.
+- For each modified or created file: the filename on a separate line in backticks, followed by a concise description of what changed.
+- Do not include full file contents or long code blocks in `## Changes` unless the user explicitly asks for code text.
+- If code snippets are necessary, include only the minimal relevant excerpt.
 - End with a suggested git commit message in English.

 #### Reporting Out-of-Scope Issues
@@ -429,4 +433,3 @@ Every patch must be **atomic and production-safe**.
 * **No transitional states** — no placeholders, incomplete refactors, or temporary inconsistencies.

 **Invariant:** After any single patch, the repository remains fully functional and buildable.
-
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2404,9 +2404,9 @@ checksum = "f87165f0995f63a9fbeea62b64d10b4d9d8e78ec6d7d51fb2125fda7bb36788f"

 [[package]]
 name = "rustls-webpki"
-version = "0.103.12"
+version = "0.103.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8279bb85272c9f10811ae6a6c547ff594d6a7f3c6c6b02ee9726d1d0dcfcdd06"
+checksum = "61c429a8649f110dddef65e2a5ad240f747e85f7758a6bccc7e5777bd33f756e"
 dependencies = [
 "aws-lc-rs",
 "ring",
@@ -2791,7 +2791,7 @@ checksum = "7b2093cf4c8eb1e67749a6762251bc9cd836b6fc171623bd0a9d324d37af2417"

 [[package]]
 name = "telemt"
-version = "3.4.6"
+version = "3.4.11"
 dependencies = [
 "aes",
 "anyhow",
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "telemt"
-version = "3.4.6"
+version = "3.4.11"
 edition = "2024"

 [features]
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # Telemt - MTProxy on Rust + Tokio

-[![Latest Release](https://img.shields.io/github/v/release/telemt/telemt?color=neon)](https://github.com/telemt/telemt/releases/latest) [![Stars](https://img.shields.io/github/stars/telemt/telemt?style=social)](https://github.com/telemt/telemt/stargazers) [![Forks](https://img.shields.io/github/forks/telemt/telemt?style=social)](https://github.com/telemt/telemt/network/members) [![Telegram](https://img.shields.io/badge/Telegram-Chat-24a1de?logo=telegram&logoColor=24a1de)](https://t.me/telemtrs)
+[![Latest Release](https://img.shields.io/github/v/release/telemt/telemt?color=neon)](https://github.com/telemt/telemt/releases/latest) [![Stars](https://img.shields.io/github/stars/telemt/telemt?style=social)](https://github.com/telemt/telemt/stargazers) [![Forks](https://img.shields.io/github/forks/telemt/telemt?style=social)](https://github.com/telemt/telemt/network/members)

 [🇷🇺 README на русском](https://github.com/telemt/telemt/blob/main/README.ru.md)

@@ -14,7 +14,7 @@

 <p align="center">
  <a href="https://t.me/telemtrs">
-    <img src="/docs/assets/telegram_button.svg" width="150"/>
+    <img src="https://github.com/user-attachments/assets/30b7e7b9-974a-4e3d-aab6-b58a85de4507" width="240"/>
  </a>
 </p>

@@ -99,7 +99,7 @@ Monero (XMR) directly:
 8Bk4tZEYPQWSypeD2hrUXG2rKbAKF16GqEN942ZdAP5cFdSqW6h4DwkP5cJMAdszzuPeHeHZPTyjWWFwzeFdjuci3ktfMoB
 ```

-All donations go toward infrastructure, development, and research.
+All donations go toward infrastructure, development and research


 ![telemt_scheme](docs/assets/telemt.png)
--- a/docs/Architecture/API/API.md
+++ b/docs/Architecture/API/API.md
@@ -13,7 +13,7 @@ API runtime is configured in `[server.api]`.
 | `listen` | `string` (`IP:PORT`) | `0.0.0.0:9091` | API bind address. |
 | `whitelist` | `CIDR[]` | `127.0.0.0/8` | Source IP allowlist. Empty list means allow all. |
 | `auth_header` | `string` | `""` | Exact value for `Authorization` header. Empty disables header auth. |
-| `request_body_limit_bytes` | `usize` | `65536` | Maximum request body size. Must be `> 0`. |
+| `request_body_limit_bytes` | `usize` | `65536` | Maximum request body size. Must be within `[1, 1048576]`. |
 | `minimal_runtime_enabled` | `bool` | `true` | Enables runtime snapshot endpoints requiring ME pool read-lock aggregation. |
 | `minimal_runtime_cache_ttl_ms` | `u64` | `1000` | Cache TTL for minimal snapshots. `0` disables cache; valid range is `[0, 60000]`. |
 | `runtime_edge_enabled` | `bool` | `false` | Enables runtime edge endpoints with cached aggregation payloads. |
@@ -26,7 +26,7 @@ API runtime is configured in `[server.api]`.

 Runtime validation for API config:
 - `server.api.listen` must be a valid `IP:PORT`.
- `server.api.request_body_limit_bytes` must be `> 0`.
+- `server.api.request_body_limit_bytes` must be within `[1, 1048576]`.
 - `server.api.minimal_runtime_cache_ttl_ms` must be within `[0, 60000]`.
 - `server.api.runtime_edge_cache_ttl_ms` must be within `[0, 60000]`.
 - `server.api.runtime_edge_top_n` must be within `[1, 1000]`.
@@ -76,13 +76,14 @@ Requests are processed in this order:

 Notes:
 - Whitelist is evaluated against the direct TCP peer IP (`SocketAddr::ip`), without `X-Forwarded-For` support.
- `Authorization` check is exact string equality against configured `auth_header`.
+- `Authorization` check is exact constant-time byte equality against configured `auth_header`.

 ## Endpoint Matrix

 | Method | Path | Body | Success | `data` contract |
 | --- | --- | --- | --- | --- |
 | `GET` | `/v1/health` | none | `200` | `HealthData` |
+| `GET` | `/v1/health/ready` | none | `200` or `503` | `HealthReadyData` |
 | `GET` | `/v1/system/info` | none | `200` | `SystemInfoData` |
 | `GET` | `/v1/runtime/gates` | none | `200` | `RuntimeGatesData` |
 | `GET` | `/v1/runtime/initialization` | none | `200` | `RuntimeInitializationData` |
@@ -102,13 +103,50 @@ Notes:
 | `GET` | `/v1/runtime/me-selftest` | none | `200` | `RuntimeMeSelftestData` |
 | `GET` | `/v1/runtime/connections/summary` | none | `200` | `RuntimeEdgeConnectionsSummaryData` |
 | `GET` | `/v1/runtime/events/recent` | none | `200` | `RuntimeEdgeEventsData` |
+| `GET` | `/v1/stats/users/active-ips` | none | `200` | `UserActiveIps[]` |
 | `GET` | `/v1/stats/users` | none | `200` | `UserInfo[]` |
 | `GET` | `/v1/users` | none | `200` | `UserInfo[]` |
-| `POST` | `/v1/users` | `CreateUserRequest` | `201` | `CreateUserResponse` |
+| `POST` | `/v1/users` | `CreateUserRequest` | `201` or `202` | `CreateUserResponse` |
 | `GET` | `/v1/users/{username}` | none | `200` | `UserInfo` |
-| `PATCH` | `/v1/users/{username}` | `PatchUserRequest` | `200` | `UserInfo` |
-| `DELETE` | `/v1/users/{username}` | none | `200` | `string` (deleted username) |
-| `POST` | `/v1/users/{username}/rotate-secret` | `RotateSecretRequest` or empty body | `404` | `ErrorResponse` (`not_found`, current runtime behavior) |
+| `PATCH` | `/v1/users/{username}` | `PatchUserRequest` | `200` or `202` | `UserInfo` |
+| `DELETE` | `/v1/users/{username}` | none | `200` or `202` | `DeleteUserResponse` |
+| `POST` | `/v1/users/{username}/rotate-secret` | `RotateSecretRequest` or empty body | `200` or `202` | `CreateUserResponse` |
+| `POST` | `/v1/users/{username}/reset-quota` | empty body | `200` | `ResetUserQuotaResponse` |
+
+## Endpoint Behavior
+
+| Endpoint | Function |
+| --- | --- |
+| `GET /v1/health` | Returns basic API liveness and current `read_only` flag. |
+| `GET /v1/health/ready` | Returns readiness based on admission state and upstream health; returns `503` when not ready. |
+| `GET /v1/system/info` | Returns binary/build metadata, process uptime, config path/hash, and reload counters. |
+| `GET /v1/runtime/gates` | Returns admission, ME readiness, fallback/reroute, and startup gate state. |
+| `GET /v1/runtime/initialization` | Returns startup progress, ME initialization status, and per-component timeline. |
+| `GET /v1/limits/effective` | Returns effective timeout, upstream, ME, unique-IP, and TCP policy values after config defaults/resolution. |
+| `GET /v1/security/posture` | Returns current API/security/telemetry posture flags. |
+| `GET /v1/security/whitelist` | Returns configured API whitelist CIDRs. |
+| `GET /v1/stats/summary` | Returns compact core counters and classed failure counters. |
+| `GET /v1/stats/zero/all` | Returns zero-cost core, upstream, ME, pool, and desync counters. |
+| `GET /v1/stats/upstreams` | Returns upstream zero counters and, when enabled/available, runtime upstream health rows. |
+| `GET /v1/stats/minimal/all` | Returns cached minimal ME writer/DC/runtime/network-path snapshot. |
+| `GET /v1/stats/me-writers` | Returns cached ME writer coverage and per-writer status rows. |
+| `GET /v1/stats/dcs` | Returns cached per-DC endpoint/writer/load status rows. |
+| `GET /v1/runtime/me_pool_state` | Returns active/warm/pending/draining generation state, writer contour/health, and refill state. |
+| `GET /v1/runtime/me_quality` | Returns ME lifecycle counters, route-drop counters, family states, drain gate, and per-DC RTT/coverage. |
+| `GET /v1/runtime/upstream_quality` | Returns upstream policy/counters plus runtime upstream health rows when available. |
+| `GET /v1/runtime/nat_stun` | Returns NAT/STUN runtime flags, configured/live STUN servers, reflection cache, and backoff. |
+| `GET /v1/runtime/me-selftest` | Returns ME self-test state for KDF, time skew, IP family, PID, and SOCKS BND observations. |
+| `GET /v1/runtime/connections/summary` | Returns runtime-edge connection totals and top-N users by connections/throughput. |
+| `GET /v1/runtime/events/recent` | Returns recent API/runtime event records with optional `limit` query. |
+| `GET /v1/stats/users/active-ips` | Returns users that currently have non-empty active source-IP lists. |
+| `GET /v1/stats/users` | Alias of `GET /v1/users`; returns disk-first user views with runtime lag flag. |
+| `GET /v1/users` | Returns disk-first user views sorted by username. |
+| `POST /v1/users` | Creates a user and returns the effective user view plus secret. |
+| `GET /v1/users/{username}` | Returns one disk-first user view or `404` when absent. |
+| `PATCH /v1/users/{username}` | Updates selected per-user fields with JSON Merge Patch semantics. |
+| `DELETE /v1/users/{username}` | Deletes one user and related per-user access-map entries. |
+| `POST /v1/users/{username}/rotate-secret` | Rotates one user's secret and returns the effective secret. |
+| `POST /v1/users/{username}/reset-quota` | Resets one user's runtime quota counter and persists quota state. |

 ## Common Error Codes

@@ -118,7 +156,7 @@ Notes:
 | `401` | `unauthorized` | Missing/invalid `Authorization` when `auth_header` is configured. |
 | `403` | `forbidden` | Source IP is not allowed by whitelist. |
 | `403` | `read_only` | Mutating endpoint called while `read_only=true`. |
-| `404` | `not_found` | Unknown route, unknown user, or unsupported sub-route (including current `rotate-secret` route). |
+| `404` | `not_found` | Unknown route, unknown user, or unsupported sub-route. |
 | `405` | `method_not_allowed` | Unsupported method for `/v1/users/{username}` route shape. |
 | `409` | `revision_conflict` | `If-Match` revision mismatch. |
 | `409` | `user_exists` | User already exists on create. |
@@ -132,11 +170,12 @@ Notes:
 | Case | Behavior |
 | --- | --- |
 | Path matching | Exact match on `req.uri().path()`. Query string does not affect route matching. |
-| Trailing slash | Not normalized. Example: `/v1/users/` is `404`. |
+| Trailing slash | Trimmed for route matching when path length is greater than 1. Example: `/v1/users/` matches `/v1/users`. |
 | Username route with extra slash | `/v1/users/{username}/...` is not treated as user route and returns `404`. |
 | `PUT /v1/users/{username}` | `405 method_not_allowed`. |
 | `POST /v1/users/{username}` | `404 not_found`. |
-| `POST /v1/users/{username}/rotate-secret` | `404 not_found` in current release due route matcher limitation. |
+| `POST /v1/users/{username}/rotate-secret/` | Trailing slash is trimmed and the route matches `rotate-secret`. |
+| `POST /v1/users/{username}/reset-quota/` | Trailing slash is trimmed and the route matches `reset-quota`. |

 ## Body and JSON Semantics

@@ -146,7 +185,7 @@ Notes:
 - Invalid JSON returns `400 bad_request` (`Invalid JSON body`).
 - `Content-Type` is not required for JSON parsing.
 - Unknown JSON fields are ignored by deserialization.
- `PATCH` updates only provided fields and does not support explicit clearing of optional fields.
+- `PATCH` uses JSON Merge Patch semantics for optional per-user fields: omitted means unchanged, explicit `null` removes the config entry, and a non-null value sets it.
 - `If-Match` supports both quoted and unquoted values; surrounding whitespace is trimmed.

 ## Query Parameters
@@ -166,24 +205,43 @@ Notes:
 | `max_tcp_conns` | `usize` | no | Per-user concurrent TCP limit. |
 | `expiration_rfc3339` | `string` | no | RFC3339 expiration timestamp. |
 | `data_quota_bytes` | `u64` | no | Per-user traffic quota. |
+| `rate_limit_up_bps` | `u64` | no | Per-user upload rate limit in bytes per second. |
+| `rate_limit_down_bps` | `u64` | no | Per-user download rate limit in bytes per second. |
 | `max_unique_ips` | `usize` | no | Per-user unique source IP limit. |

 ### `PatchUserRequest`
 | Field | Type | Required | Description |
 | --- | --- | --- | --- |
 | `secret` | `string` | no | Exactly 32 hex chars. |
-| `user_ad_tag` | `string` | no | Exactly 32 hex chars. |
-| `max_tcp_conns` | `usize` | no | Per-user concurrent TCP limit. |
-| `expiration_rfc3339` | `string` | no | RFC3339 expiration timestamp. |
-| `data_quota_bytes` | `u64` | no | Per-user traffic quota. |
-| `max_unique_ips` | `usize` | no | Per-user unique source IP limit. |
+| `user_ad_tag` | `string|null` | no | Exactly 32 hex chars; `null` removes the per-user ad tag. |
+| `max_tcp_conns` | `usize|null` | no | Per-user concurrent TCP limit; `null` removes the per-user override. |
+| `expiration_rfc3339` | `string|null` | no | RFC3339 expiration timestamp; `null` removes the expiration. |
+| `data_quota_bytes` | `u64|null` | no | Per-user traffic quota; `null` removes the per-user quota. |
+| `rate_limit_up_bps` | `u64|null` | no | Per-user upload rate limit in bytes per second; `null` removes the upload direction limit. |
+| `rate_limit_down_bps` | `u64|null` | no | Per-user download rate limit in bytes per second; `null` removes the download direction limit. |
+| `max_unique_ips` | `usize|null` | no | Per-user unique source IP limit; `null` removes the per-user override. |
+
+### `access.user_source_deny` via API
+- In current API surface, per-user deny-list is **not** exposed as a dedicated field in `CreateUserRequest` / `PatchUserRequest`.
+- Configure it in `config.toml` under `[access.user_source_deny]` and apply via normal config reload path.
+- Runtime behavior after apply:
+  - auth succeeds for username/secret
+  - source IP is checked against `access.user_source_deny[username]`
+  - on match, handshake is rejected with the same fail-closed outcome as invalid auth
+
+Example config:
+```toml
+[access.user_source_deny]
+alice = ["203.0.113.0/24", "2001:db8:abcd::/48"]
+bob = ["198.51.100.42/32"]
+```

 ### `RotateSecretRequest`
 | Field | Type | Required | Description |
 | --- | --- | --- | --- |
 | `secret` | `string` | no | Exactly 32 hex chars. If missing, generated automatically. |

-Note: the request contract is defined, but the corresponding route currently returns `404` (see routing edge cases).
+An empty request body is accepted and generates a new secret automatically.

 ## Response Data Contracts

@@ -193,15 +251,33 @@ Note: the request contract is defined, but the corresponding route currently ret
 | `status` | `string` | Always `"ok"`. |
 | `read_only` | `bool` | Mirrors current API `read_only` mode. |

+### `HealthReadyData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `ready` | `bool` | `true` when admission is open and at least one upstream is healthy. |
+| `status` | `string` | `"ready"` or `"not_ready"`. |
+| `reason` | `string?` | `admission_closed` or `no_healthy_upstreams` when not ready. |
+| `admission_open` | `bool` | Current admission-gate state. |
+| `healthy_upstreams` | `usize` | Number of healthy upstream entries. |
+| `total_upstreams` | `usize` | Number of configured upstream entries. |
+
 ### `SummaryData`
 | Field | Type | Description |
 | --- | --- | --- |
 | `uptime_seconds` | `f64` | Process uptime in seconds. |
 | `connections_total` | `u64` | Total accepted client connections. |
 | `connections_bad_total` | `u64` | Failed/invalid client connections. |
+| `connections_bad_by_class` | `ClassCount[]` | Failed/invalid connections grouped by class. |
+| `handshake_failures_by_class` | `ClassCount[]` | Handshake failures grouped by class. |
 | `handshake_timeouts_total` | `u64` | Handshake timeout count. |
 | `configured_users` | `usize` | Number of configured users in config. |

+#### `ClassCount`
+| Field | Type | Description |
+| --- | --- | --- |
+| `class` | `string` | Failure class label. |
+| `total` | `u64` | Counter value for this class. |
+
 ### `SystemInfoData`
 | Field | Type | Description |
 | --- | --- | --- |
@@ -226,7 +302,12 @@ Note: the request contract is defined, but the corresponding route currently ret
 | `conditional_cast_enabled` | `bool` | Whether conditional ME admission logic is enabled (`general.use_middle_proxy`). |
 | `me_runtime_ready` | `bool` | Current ME runtime readiness status used for conditional gate decisions. |
 | `me2dc_fallback_enabled` | `bool` | Whether ME -> direct fallback is enabled. |
+| `me2dc_fast_enabled` | `bool` | Whether fast ME -> direct fallback is enabled. |
 | `use_middle_proxy` | `bool` | Current transport mode preference. |
+| `route_mode` | `string` | Current route mode label from route runtime controller. |
+| `reroute_active` | `bool` | `true` when ME fallback currently routes new sessions to Direct-DC. |
+| `reroute_to_direct_at_epoch_secs` | `u64?` | Unix timestamp when current direct reroute began. |
+| `reroute_reason` | `string?` | `fast_not_ready_fallback` or `strict_grace_fallback` while reroute is active. |
 | `startup_status` | `string` | Startup status (`pending`, `initializing`, `ready`, `failed`, `skipped`). |
 | `startup_stage` | `string` | Current startup stage identifier. |
 | `startup_progress_pct` | `f64` | Startup progress percentage (`0..100`). |
@@ -277,11 +358,13 @@ Note: the request contract is defined, but the corresponding route currently ret
 | `upstream` | `EffectiveUpstreamLimits` | Effective upstream connect/retry limits. |
 | `middle_proxy` | `EffectiveMiddleProxyLimits` | Effective ME pool/floor/reconnect limits. |
 | `user_ip_policy` | `EffectiveUserIpPolicyLimits` | Effective unique-IP policy mode/window. |
+| `user_tcp_policy` | `EffectiveUserTcpPolicyLimits` | Effective per-user TCP connection policy. |

 #### `EffectiveTimeoutLimits`
 | Field | Type | Description |
 | --- | --- | --- |
 | `client_handshake_secs` | `u64` | Client handshake timeout. |
+| `client_first_byte_idle_secs` | `u64` | First-byte idle timeout before protocol classification. |
 | `tg_connect_secs` | `u64` | Upstream Telegram connect timeout. |
 | `client_keepalive_secs` | `u64` | Client keepalive interval. |
 | `client_ack_secs` | `u64` | ACK timeout. |
@@ -320,13 +403,20 @@ Note: the request contract is defined, but the corresponding route currently ret
 | `writer_pick_mode` | `string` | Writer picker mode (`sorted_rr`, `p2c`). |
 | `writer_pick_sample_size` | `u8` | Candidate sample size for `p2c` picker mode. |
 | `me2dc_fallback` | `bool` | Effective ME -> direct fallback flag. |
+| `me2dc_fast` | `bool` | Effective fast fallback flag. |

 #### `EffectiveUserIpPolicyLimits`
 | Field | Type | Description |
 | --- | --- | --- |
+| `global_each` | `usize` | Global per-user unique-IP limit applied when no per-user override exists. |
 | `mode` | `string` | Unique-IP policy mode (`active_window`, `time_window`, `combined`). |
 | `window_secs` | `u64` | Time window length used by unique-IP policy. |

+#### `EffectiveUserTcpPolicyLimits`
+| Field | Type | Description |
+| --- | --- | --- |
+| `global_each` | `usize` | Global per-user concurrent TCP limit applied when no per-user override exists. |
+
 ### `SecurityPostureData`
 | Field | Type | Description |
 | --- | --- | --- |
@@ -430,6 +520,8 @@ Note: the request contract is defined, but the corresponding route currently ret
 | --- | --- | --- |
 | `counters` | `RuntimeMeQualityCountersData` | Key ME lifecycle/error counters. |
 | `route_drops` | `RuntimeMeQualityRouteDropData` | Route drop counters by reason. |
+| `family_states` | `RuntimeMeQualityFamilyStateData[]` | Per-family ME route/recovery state rows. |
+| `drain_gate` | `RuntimeMeQualityDrainGateData` | Current ME drain-gate decision state. |
 | `dc_rtt` | `RuntimeMeQualityDcRttData[]` | Per-DC RTT and writer coverage rows. |

 #### `RuntimeMeQualityCountersData`
@@ -451,6 +543,24 @@ Note: the request contract is defined, but the corresponding route currently ret
 | `queue_full_base_total` | `u64` | Route drops in base-queue path. |
 | `queue_full_high_total` | `u64` | Route drops in high-priority queue path. |

+#### `RuntimeMeQualityFamilyStateData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `family` | `string` | Address family label. |
+| `state` | `string` | Current family state label. |
+| `state_since_epoch_secs` | `u64` | Unix timestamp when current state began. |
+| `suppressed_until_epoch_secs` | `u64?` | Unix timestamp until suppression remains active. |
+| `fail_streak` | `u32` | Consecutive failure count. |
+| `recover_success_streak` | `u32` | Consecutive recovery success count. |
+
+#### `RuntimeMeQualityDrainGateData`
+| Field | Type | Description |
+| --- | --- | --- |
+| `route_quorum_ok` | `bool` | Whether route quorum condition allows drain. |
+| `redundancy_ok` | `bool` | Whether redundancy condition allows drain. |
+| `block_reason` | `string` | Current drain block reason label. |
+| `updated_at_epoch_secs` | `u64` | Unix timestamp of the latest gate update. |
+
 #### `RuntimeMeQualityDcRttData`
 | Field | Type | Description |
 | --- | --- | --- |
@@ -713,11 +823,24 @@ Note: the request contract is defined, but the corresponding route currently ret
 | `uptime_seconds` | `f64` | Process uptime. |
 | `connections_total` | `u64` | Total accepted connections. |
 | `connections_bad_total` | `u64` | Failed/invalid connections. |
+| `connections_bad_by_class` | `ClassCount[]` | Failed/invalid connections grouped by class. |
+| `handshake_failures_by_class` | `ClassCount[]` | Handshake failures grouped by class. |
 | `handshake_timeouts_total` | `u64` | Handshake timeouts. |
+| `accept_permit_timeout_total` | `u64` | Listener admission permit acquisition timeouts. |
 | `configured_users` | `usize` | Configured user count. |
 | `telemetry_core_enabled` | `bool` | Core telemetry toggle. |
 | `telemetry_user_enabled` | `bool` | User telemetry toggle. |
 | `telemetry_me_level` | `string` | ME telemetry level (`off|normal|verbose`). |
+| `conntrack_control_enabled` | `bool` | Whether conntrack control is enabled by policy. |
+| `conntrack_control_available` | `bool` | Whether conntrack control backend is currently available. |
+| `conntrack_pressure_active` | `bool` | Current conntrack pressure flag. |
+| `conntrack_event_queue_depth` | `u64` | Current conntrack close-event queue depth. |
+| `conntrack_rule_apply_ok` | `bool` | Last conntrack rule application state. |
+| `conntrack_delete_attempt_total` | `u64` | Conntrack delete attempts. |
+| `conntrack_delete_success_total` | `u64` | Successful conntrack deletes. |
+| `conntrack_delete_not_found_total` | `u64` | Conntrack delete misses. |
+| `conntrack_delete_error_total` | `u64` | Conntrack delete errors. |
+| `conntrack_close_event_drop_total` | `u64` | Dropped conntrack close events. |

 #### `ZeroUpstreamData`
 | Field | Type | Description |
@@ -804,6 +927,24 @@ Note: the request contract is defined, but the corresponding route currently ret
 | `route_drop_queue_full_total` | `u64` | Route drops due to full queue (total). |
 | `route_drop_queue_full_base_total` | `u64` | Route drops in base queue mode. |
 | `route_drop_queue_full_high_total` | `u64` | Route drops in high queue mode. |
+| `d2c_batches_total` | `u64` | ME D->C batch flushes. |
+| `d2c_batch_frames_total` | `u64` | ME D->C frames included in batches. |
+| `d2c_batch_bytes_total` | `u64` | ME D->C payload bytes included in batches. |
+| `d2c_flush_reason_queue_drain_total` | `u64` | Flushes caused by queue drain. |
+| `d2c_flush_reason_batch_frames_total` | `u64` | Flushes caused by frame-count batch limit. |
+| `d2c_flush_reason_batch_bytes_total` | `u64` | Flushes caused by byte-count batch limit. |
+| `d2c_flush_reason_max_delay_total` | `u64` | Flushes caused by max-delay budget. |
+| `d2c_flush_reason_ack_immediate_total` | `u64` | Flushes caused by immediate ACK policy. |
+| `d2c_flush_reason_close_total` | `u64` | Flushes caused by close path. |
+| `d2c_data_frames_total` | `u64` | ME D->C data frames. |
+| `d2c_ack_frames_total` | `u64` | ME D->C ACK frames. |
+| `d2c_payload_bytes_total` | `u64` | ME D->C payload bytes. |
+| `d2c_write_mode_coalesced_total` | `u64` | Coalesced D->C writes. |
+| `d2c_write_mode_split_total` | `u64` | Split D->C writes. |
+| `d2c_quota_reject_pre_write_total` | `u64` | D->C quota rejects before write. |
+| `d2c_quota_reject_post_write_total` | `u64` | D->C quota rejects after write. |
+| `d2c_frame_buf_shrink_total` | `u64` | D->C frame-buffer shrink operations. |
+| `d2c_frame_buf_shrink_bytes_total` | `u64` | Bytes released by D->C frame-buffer shrink operations. |
 | `socks_kdf_strict_reject_total` | `u64` | SOCKS KDF strict rejects. |
 | `socks_kdf_compat_fallback_total` | `u64` | SOCKS KDF compat fallbacks. |
 | `endpoint_quarantine_total` | `u64` | Endpoint quarantine activations. |
@@ -963,6 +1104,8 @@ Note: the request contract is defined, but the corresponding route currently ret
 | `required_writers` | `usize` | Required writers based on current floor policy. |
 | `alive_writers` | `usize` | Writers currently alive. |
 | `coverage_pct` | `f64` | `alive_writers / required_writers * 100`. |
+| `fresh_alive_writers` | `usize` | Alive writers that match freshness requirements. |
+| `fresh_coverage_pct` | `f64` | `fresh_alive_writers / required_writers * 100`. |

 #### `MeWriterStatus`
 | Field | Type | Description |
@@ -977,6 +1120,12 @@ Note: the request contract is defined, but the corresponding route currently ret
 | `bound_clients` | `usize` | Number of currently bound clients. |
 | `idle_for_secs` | `u64?` | Idle age in seconds if idle. |
 | `rtt_ema_ms` | `f64?` | RTT exponential moving average. |
+| `matches_active_generation` | `bool` | Whether this writer belongs to the active pool generation. |
+| `in_desired_map` | `bool` | Whether this writer's endpoint remains in desired topology. |
+| `allow_drain_fallback` | `bool` | Whether drain fallback is allowed for this writer. |
+| `drain_started_at_epoch_secs` | `u64?` | Unix timestamp when drain started. |
+| `drain_deadline_epoch_secs` | `u64?` | Unix timestamp of drain deadline. |
+| `drain_over_ttl` | `bool` | Whether drain has exceeded its TTL. |

 ### `DcStatusData`
 | Field | Type | Description |
@@ -1001,6 +1150,8 @@ Note: the request contract is defined, but the corresponding route currently ret
 | `floor_capped` | `bool` | `true` when computed floor target was capped by active limits. |
 | `alive_writers` | `usize` | Alive writers in this DC. |
 | `coverage_pct` | `f64` | `alive_writers / required_writers * 100`. |
+| `fresh_alive_writers` | `usize` | Fresh alive writers in this DC. |
+| `fresh_coverage_pct` | `f64` | `fresh_alive_writers / required_writers * 100`. |
 | `rtt_ms` | `f64?` | Aggregated RTT for DC. |
 | `load` | `usize` | Active client sessions bound to this DC. |

@@ -1014,10 +1165,13 @@ Note: the request contract is defined, but the corresponding route currently ret
 | Field | Type | Description |
 | --- | --- | --- |
 | `username` | `string` | Username. |
+| `in_runtime` | `bool` | Whether current runtime config already contains this user. |
 | `user_ad_tag` | `string?` | Optional ad tag (32 hex chars). |
 | `max_tcp_conns` | `usize?` | Optional max concurrent TCP limit. |
 | `expiration_rfc3339` | `string?` | Optional expiration timestamp. |
 | `data_quota_bytes` | `u64?` | Optional data quota. |
+| `rate_limit_up_bps` | `u64?` | Optional upload rate limit in bytes per second. |
+| `rate_limit_down_bps` | `u64?` | Optional download rate limit in bytes per second. |
 | `max_unique_ips` | `usize?` | Optional unique IP limit. |
 | `current_connections` | `u64` | Current live connections. |
 | `active_unique_ips` | `usize` | Current active unique source IPs. |
@@ -1027,12 +1181,25 @@ Note: the request contract is defined, but the corresponding route currently ret
 | `total_octets` | `u64` | Total traffic octets for this user. |
 | `links` | `UserLinks` | Active connection links derived from current config. |

+### `UserActiveIps`
+| Field | Type | Description |
+| --- | --- | --- |
+| `username` | `string` | Username with at least one active tracked source IP. |
+| `active_ips` | `ip[]` | Active source IPs for this user. |
+
 #### `UserLinks`
 | Field | Type | Description |
 | --- | --- | --- |
 | `classic` | `string[]` | Active `tg://proxy` links for classic mode. |
 | `secure` | `string[]` | Active `tg://proxy` links for secure/DD mode. |
 | `tls` | `string[]` | Active `tg://proxy` links for EE-TLS mode (for each host+TLS domain). |
+| `tls_domains` | `TlsDomainLink[]` | Extra TLS-domain links as explicit domain/link pairs for `censorship.tls_domains`. |
+
+#### `TlsDomainLink`
+| Field | Type | Description |
+| --- | --- | --- |
+| `domain` | `string` | TLS domain represented by the link. |
+| `link` | `string` | `tg://proxy` link for this domain. |

 Link generation uses active config and enabled modes:
 - Link port is `general.links.public_port` when configured; otherwise `server.port`.
@@ -1052,13 +1219,27 @@ Link generation uses active config and enabled modes:
 | `user` | `UserInfo` | Created or updated user view. |
 | `secret` | `string` | Effective user secret. |

+### `DeleteUserResponse`
+| Field | Type | Description |
+| --- | --- | --- |
+| `username` | `string` | Deleted username. |
+| `in_runtime` | `bool` | `true` when runtime config still contains the user and hot-reload has not applied deletion yet. |
+
+### `ResetUserQuotaResponse`
+| Field | Type | Description |
+| --- | --- | --- |
+| `username` | `string` | User whose runtime quota counter was reset. |
+| `used_bytes` | `u64` | Current used bytes after reset; always `0` on success. |
+| `last_reset_epoch_secs` | `u64` | Unix timestamp of the reset operation. |
+
 ## Mutation Semantics

 | Endpoint | Notes |
 | --- | --- |
 | `POST /v1/users` | Creates user, validates config, then atomically updates only affected `access.*` TOML tables (`access.users` always, plus optional per-user tables present in request). |
-| `PATCH /v1/users/{username}` | Partial update of provided fields only. Missing fields remain unchanged. Current implementation persists full config document on success. |
-| `POST /v1/users/{username}/rotate-secret` | Currently returns `404` in runtime route matcher; request schema is reserved for intended behavior. |
+| `PATCH /v1/users/{username}` | Partial update of provided fields only. Missing fields remain unchanged; explicit `null` removes optional per-user entries. The write path updates only affected `access.*` TOML tables. |
+| `POST /v1/users/{username}/rotate-secret` | Replaces the user's secret with a provided valid 32-hex value or a generated value, then returns the effective secret in `CreateUserResponse`. |
+| `POST /v1/users/{username}/reset-quota` | Resets the runtime quota counter for the route username, persists quota state to `general.quota_state_path`, and does not modify user config. |
 | `DELETE /v1/users/{username}` | Deletes only specified user, removes this user from related optional `access.user_*` maps, blocks last-user deletion, and atomically updates only related `access.*` TOML tables. |

 All mutating endpoints:
@@ -1067,6 +1248,12 @@ All mutating endpoints:
 - Return new `revision` after successful write.
 - Use process-local mutation lock + atomic write (`tmp + rename`) for config persistence.

+Docker deployment note:
+- Mutating endpoints require `config.toml` to live inside a writable mounted directory.
+- Do not mount `config.toml` as a single bind-mounted file when API mutations are enabled; atomic `tmp + rename` writes can fail with `Device or resource busy`.
+- Mount the config directory instead, for example `./config:/etc/telemt:rw`, and start Telemt with `/etc/telemt/config.toml`.
+- A read-only single-file mount remains valid only for read-only deployments or when `[server.api].read_only=true`.
+
 Delete path cleanup guarantees:
 - Config cleanup removes only the requested username keys.
 - Runtime unique-IP cleanup removes only this user's limiter and tracked IP state.
@@ -1133,5 +1320,4 @@ When `general.use_middle_proxy=true` and `general.me2dc_fallback=true`:

 ## Known Limitations (Current Release)

- `POST /v1/users/{username}/rotate-secret` is currently unreachable in route matcher and returns `404`.
 - API runtime controls under `server.api` are documented as restart-required; hot-reload behavior for these fields is not strictly uniform in all change combinations.
--- a/docs/Architecture/Fronting-splitting/TLS_FRONT_PROFILE_FIDELITY.en.md
+++ b/docs/Architecture/Fronting-splitting/TLS_FRONT_PROFILE_FIDELITY.en.md
@@ -128,7 +128,48 @@ Recommended for cleaner testing:

 Persisted cache artifacts are useful, but they are not required if packet captures already demonstrate the runtime result.

-### 4. Capture a direct-origin trace
+### 4. Check TLS-front profile health metrics
+
+If the metrics endpoint is enabled, check the TLS-front profile health before packet-capture validation:
+
+```bash
+curl -s http://127.0.0.1:9999/metrics | grep -E 'telemt_tls_front_profile|telemt_tls_fetch_profile_cache|telemt_tls_front_full_cert'
+```
+
+The profile-health metrics expose the runtime state of configured TLS front domains:
+
+- `telemt_tls_front_profile_domains` shows configured, emitted, and suppressed domain series.
+- `telemt_tls_front_profile_info` shows profile source and feature flags per domain.
+- `telemt_tls_front_profile_age_seconds` shows cached profile age.
+- `telemt_tls_front_profile_app_data_records` shows cached AppData record count.
+- `telemt_tls_front_profile_ticket_records` shows cached ticket-like tail record count.
+- `telemt_tls_front_profile_change_cipher_spec_records` shows cached ChangeCipherSpec count.
+- `telemt_tls_front_profile_app_data_bytes` shows total cached AppData bytes.
+
+Interpretation:
+
+- `source="merged"` or `source="raw"` means real TLS profile data is being used.
+- `source="default"` or `is_default="true"` means the domain currently uses the synthetic default fallback.
+- `has_cert_payload="true"` means certificate payload data is available for TLS emulation.
+- Non-zero AppData/ticket/CCS counters show captured server-flight shape.
+
+Example healthy output:
+
+```text
+telemt_tls_front_profile_domains{status="configured"} 1
+telemt_tls_front_profile_domains{status="emitted"} 1
+telemt_tls_front_profile_domains{status="suppressed"} 0
+telemt_tls_front_profile_info{domain="itunes.apple.com",source="merged",is_default="false",has_cert_info="true",has_cert_payload="true"} 1
+telemt_tls_front_profile_age_seconds{domain="itunes.apple.com"} 20
+telemt_tls_front_profile_app_data_records{domain="itunes.apple.com"} 3
+telemt_tls_front_profile_ticket_records{domain="itunes.apple.com"} 1
+telemt_tls_front_profile_change_cipher_spec_records{domain="itunes.apple.com"} 1
+telemt_tls_front_profile_app_data_bytes{domain="itunes.apple.com"} 5240
+```
+
+These metrics do not prove byte-level origin equivalence. They are an operational health signal that the configured domain is backed by real cached profile data instead of default fallback data.
+
+### 5. Capture a direct-origin trace

 From a separate client host, connect directly to the origin:

@@ -142,7 +183,7 @@ Capture with:
 sudo tcpdump -i any -w origin-direct.pcap host ORIGIN_IP and port 443
 ```

-### 5. Capture a Telemt FakeTLS success-path trace
+### 6. Capture a Telemt FakeTLS success-path trace

 Now connect to Telemt with a real Telegram client through an `ee` proxy link that targets the Telemt instance.

@@ -154,7 +195,7 @@ Capture with:
 sudo tcpdump -i any -w telemt-emulated.pcap host TELEMT_IP and port 443
 ```

-### 6. Decode TLS record structure
+### 7. Decode TLS record structure

 Use `tshark` to print record-level structure:

@@ -182,7 +223,7 @@ Focus on the server flight after ClientHello:
 - `20` = ChangeCipherSpec
 - `23` = ApplicationData

-### 7. Build a comparison table
+### 8. Build a comparison table

 A compact table like the following is usually enough:

--- a/docs/Architecture/Fronting-splitting/TLS_FRONT_PROFILE_FIDELITY.ru.md
+++ b/docs/Architecture/Fronting-splitting/TLS_FRONT_PROFILE_FIDELITY.ru.md
@@ -126,9 +126,50 @@ openssl s_client -connect ORIGIN_IP:443 -servername YOUR_DOMAIN </dev/null
 2. Дайте ему получить TLS front profile data для выбранного домена.
 3. Если `tls_front_dir` хранится persistently, убедитесь, что TLS front cache заполнен.

-Persisted cache artifacts полезны, но не обязательны, если packet capture уже показывают runtime result.
+Сохранённые артефакты кэша полезны, но не обязательны, если packet capture уже показывает результат в runtime.

-### 4. Снять direct-origin trace
+### 4. Проверить метрики состояния TLS-front profile
+
+Если endpoint метрик включён, перед проверкой через packet capture можно быстро проверить состояние TLS-front profile:
+
+```bash
+curl -s http://127.0.0.1:9999/metrics | grep -E 'telemt_tls_front_profile|telemt_tls_fetch_profile_cache|telemt_tls_front_full_cert'
+```
+
+Метрики состояния профиля показывают runtime-состояние настроенных TLS-front доменов:
+
+- `telemt_tls_front_profile_domains` показывает количество настроенных, экспортируемых и скрытых из-за лимита доменов.
+- `telemt_tls_front_profile_info` показывает источник профиля и флаги доступных данных по каждому домену.
+- `telemt_tls_front_profile_age_seconds` показывает возраст закешированного профиля.
+- `telemt_tls_front_profile_app_data_records` показывает количество закешированных AppData records.
+- `telemt_tls_front_profile_ticket_records` показывает количество закешированных ticket-like tail records.
+- `telemt_tls_front_profile_change_cipher_spec_records` показывает закешированное количество ChangeCipherSpec records.
+- `telemt_tls_front_profile_app_data_bytes` показывает общий размер закешированных AppData bytes.
+
+Интерпретация:
+
+- `source="merged"` или `source="raw"` означает, что используются реальные данные TLS-профиля.
+- `source="default"` или `is_default="true"` означает, что домен сейчас работает на synthetic default fallback.
+- `has_cert_payload="true"` означает, что certificate payload доступен для TLS emulation.
+- Ненулевые AppData/ticket/CCS counters показывают захваченную форму server flight.
+
+Пример здорового состояния:
+
+```text
+telemt_tls_front_profile_domains{status="configured"} 1
+telemt_tls_front_profile_domains{status="emitted"} 1
+telemt_tls_front_profile_domains{status="suppressed"} 0
+telemt_tls_front_profile_info{domain="itunes.apple.com",source="merged",is_default="false",has_cert_info="true",has_cert_payload="true"} 1
+telemt_tls_front_profile_age_seconds{domain="itunes.apple.com"} 20
+telemt_tls_front_profile_app_data_records{domain="itunes.apple.com"} 3
+telemt_tls_front_profile_ticket_records{domain="itunes.apple.com"} 1
+telemt_tls_front_profile_change_cipher_spec_records{domain="itunes.apple.com"} 1
+telemt_tls_front_profile_app_data_bytes{domain="itunes.apple.com"} 5240
+```
+
+Эти метрики не доказывают побайтную эквивалентность с origin. Это эксплуатационный сигнал состояния: настроенный домен действительно основан на реальных закешированных данных профиля, а не на default fallback.
+
+### 5. Снять direct-origin trace

 С отдельной клиентской машины подключитесь напрямую к origin:

@@ -142,7 +183,7 @@ Capture:
 sudo tcpdump -i any -w origin-direct.pcap host ORIGIN_IP and port 443
 ```

-### 5. Снять Telemt FakeTLS success-path trace
+### 6. Снять Telemt FakeTLS success-path trace

 Теперь подключитесь к Telemt через реальный Telegram client с `ee` proxy link, который указывает на Telemt instance.

@@ -154,7 +195,7 @@ Capture:
 sudo tcpdump -i any -w telemt-emulated.pcap host TELEMT_IP and port 443
 ```

-### 6. Декодировать структуру TLS records
+### 7. Декодировать структуру TLS records

 Используйте `tshark`, чтобы вывести record-level structure:

@@ -182,7 +223,7 @@ tshark -r telemt-emulated.pcap -Y "tls.record" -T fields \
 - `20` = ChangeCipherSpec
 - `23` = ApplicationData

-### 7. Собрать сравнительную таблицу
+### 8. Собрать сравнительную таблицу

 Обычно достаточно короткой таблицы такого вида:

--- a/docs/Config_params/CONFIG_PARAMS.en.md
+++ b/docs/Config_params/CONFIG_PARAMS.en.md
@@ -162,6 +162,8 @@ This document lists all configuration keys accepted by `config.toml`.
 | [`log_level`](#log_level) | `"debug"`, `"verbose"`, `"normal"`, or `"silent"` | `"normal"` |
 | [`disable_colors`](#disable_colors) | `bool` | `false` |
 | [`me_socks_kdf_policy`](#me_socks_kdf_policy) | `"strict"` or `"compat"` | `"strict"` |
+| [`me_route_backpressure_enabled`](#me_route_backpressure_enabled) | `bool` | `false` |
+| [`me_route_fairshare_enabled`](#me_route_fairshare_enabled) | `bool` | `false` |
 | [`me_route_backpressure_base_timeout_ms`](#me_route_backpressure_base_timeout_ms) | `u64` | `25` |
 | [`me_route_backpressure_high_timeout_ms`](#me_route_backpressure_high_timeout_ms) | `u64` | `120` |
 | [`me_route_backpressure_high_watermark_pct`](#me_route_backpressure_high_watermark_pct) | `u8` | `80` |
@@ -975,6 +977,24 @@ This document lists all configuration keys accepted by `config.toml`.
    [general]
    me_socks_kdf_policy = "strict"
    ```
+## me_route_backpressure_enabled
+  - **Constraints / validation**: `bool`.
+  - **Description**: Enables channel-pressure-aware route send timeouts.
+  - **Example**:
+
+    ```toml
+    [general]
+    me_route_backpressure_enabled = false
+    ```
+## me_route_fairshare_enabled
+  - **Constraints / validation**: `bool`.
+  - **Description**: Enables fair-share routing admission across writer workers.
+  - **Example**:
+
+    ```toml
+    [general]
+    me_route_fairshare_enabled = false
+    ```
 ## me_route_backpressure_base_timeout_ms
  - **Constraints / validation**: Must be within `1..=5000` (milliseconds).
  - **Description**: Base backpressure timeout in milliseconds for ME route-channel send.
@@ -1753,6 +1773,7 @@ This document lists all configuration keys accepted by `config.toml`.
 | [`metrics_whitelist`](#metrics_whitelist) | `IpNetwork[]` | `["127.0.0.1/32", "::1/128"]` |
 | [`max_connections`](#max_connections) | `u32` | `10000` |
 | [`accept_permit_timeout_ms`](#accept_permit_timeout_ms) | `u64` | `250` |
+| [`listen_backlog`](#listen_backlog) | `u32` | `1024` |

 ## port
  - **Constraints / validation**: `u16`.
@@ -1763,6 +1784,15 @@ This document lists all configuration keys accepted by `config.toml`.
    [server]
    port = 443
    ```
+## listen_backlog
+  - **Constraints / validation**: `u32`. `0` uses the OS default backlog behavior.
+  - **Description**: Listen backlog passed to `listen(2)` for TCP sockets.
+  - **Example**:
+
+    ```toml
+    [server]
+    listen_backlog = 1024
+    ```
 ## listen_addr_ipv4
  - **Constraints / validation**: `String` (optional). When set, must be a valid IPv4 address string.
  - **Description**: IPv4 bind address for TCP listener (omit this key to disable IPv4 bind).
@@ -2005,6 +2035,7 @@ Note: This section also accepts the legacy alias `[server.admin_api]` (same sche
 | [`runtime_edge_top_n`](#runtime_edge_top_n) | `usize` | `10` |
 | [`runtime_edge_events_capacity`](#runtime_edge_events_capacity) | `usize` | `256` |
 | [`read_only`](#read_only) | `bool` | `false` |
+| [`gray_action`](#gray_action) | `"drop"`, `"api"`, or `"200"` | `"drop"` |

 ## enabled
  - **Constraints / validation**: `bool`.
@@ -2015,6 +2046,15 @@ Note: This section also accepts the legacy alias `[server.admin_api]` (same sche
    [server.api]
    enabled = true
    ```
+## gray_action
+  - **Constraints / validation**: `"drop"`, `"api"`, or `"200"`.
+  - **Description**: API response policy for gray/limited states: drop request, serve normal API response, or force `200 OK`.
+  - **Example**:
+
+    ```toml
+    [server.api]
+    gray_action = "drop"
+    ```
 ## listen
  - **Constraints / validation**: `String`. Must be in `IP:PORT` format.
  - **Description**: API bind address in `IP:PORT` format.
@@ -2207,6 +2247,15 @@ Note: This section also accepts the legacy alias `[server.admin_api]` (same sche
    [timeouts]
    client_handshake = 30
    ```
+## client_first_byte_idle_secs
+  - **Constraints / validation**: `u64` (seconds). `0` disables first-byte idle enforcement.
+  - **Description**: Maximum idle time to wait for the first client payload byte after session setup.
+  - **Example**:
+
+    ```toml
+    [timeouts]
+    client_first_byte_idle_secs = 300
+    ```
 ## relay_idle_policy_v2_enabled
  - **Constraints / validation**: `bool`.
  - **Description**: Enables soft/hard middle-relay client idle policy.
@@ -2311,6 +2360,7 @@ Note: This section also accepts the legacy alias `[server.admin_api]` (same sche
 | [`server_hello_delay_max_ms`](#server_hello_delay_max_ms) | `u64` | `0` |
 | [`tls_new_session_tickets`](#tls_new_session_tickets) | `u8` | `0` |
 | [`tls_full_cert_ttl_secs`](#tls_full_cert_ttl_secs) | `u64` | `90` |
+| [`serverhello_compact`](#serverhello_compact) | `bool` | `false` |
 | [`alpn_enforce`](#alpn_enforce) | `bool` | `true` |
 | [`mask_proxy_protocol`](#mask_proxy_protocol) | `u8` | `0` |
 | [`mask_shape_hardening`](#mask_shape_hardening) | `bool` | `true` |
@@ -2488,6 +2538,15 @@ Note: This section also accepts the legacy alias `[server.admin_api]` (same sche
    [censorship]
    tls_full_cert_ttl_secs = 90
    ```
+## serverhello_compact
+  - **Constraints / validation**: `bool`.
+  - **Description**: Enables compact ServerHello/Fake-TLS profile to reduce response-size signature.
+  - **Example**:
+
+    ```toml
+    [censorship]
+    serverhello_compact = false
+    ```
 ## alpn_enforce
  - **Constraints / validation**: `bool`.
  - **Description**: Enforces ALPN echo behavior based on client preference.
@@ -2827,9 +2886,12 @@ If your backend or network is very bandwidth-constrained, reduce cap first. If p
 | [`user_max_unique_ips_global_each`](#user_max_unique_ips_global_each) | `usize` | `0` |
 | [`user_max_unique_ips_mode`](#user_max_unique_ips_mode) | `"active_window"`, `"time_window"`, or `"combined"` | `"active_window"` |
 | [`user_max_unique_ips_window_secs`](#user_max_unique_ips_window_secs) | `u64` | `30` |
+| [`user_source_deny`](#user_source_deny) | `Map<String, IpNetwork[]>` | `{}` |
 | [`replay_check_len`](#replay_check_len) | `usize` | `65536` |
 | [`replay_window_secs`](#replay_window_secs) | `u64` | `120` |
 | [`ignore_time_skew`](#ignore_time_skew) | `bool` | `false` |
+| [`user_rate_limits`](#user_rate_limits) | `Map<String, RateLimitBps>` | `{}` |
+| [`cidr_rate_limits`](#cidr_rate_limits) | `Map<IpNetwork, RateLimitBps>` | `{}` |

 ## users
  - **Constraints / validation**: Must not be empty (at least one user must exist). Each value must be **exactly 32 hex characters**.
@@ -2929,6 +2991,20 @@ If your backend or network is very bandwidth-constrained, reduce cap first. If p
    [access]
    user_max_unique_ips_window_secs = 30
    ```
+## user_source_deny
+  - **Constraints / validation**: Table `username -> IpNetwork[]`. Each network must parse as CIDR (for example `203.0.113.0/24` or `2001:db8::/32`).
+  - **Description**: Per-user source IP/CIDR deny-list applied **after successful auth** in TLS and MTProto handshake paths. A matched source IP is rejected via the same fail-closed path as invalid auth.
+  - **Example**:
+
+    ```toml
+    [access.user_source_deny]
+    alice = ["203.0.113.0/24", "2001:db8:abcd::/48"]
+    bob = ["198.51.100.42/32"]
+    ```
+
+  - **How it works (quick check)**:
+    - connection from user `alice` and source `203.0.113.55` -> rejected (matches `203.0.113.0/24`)
+    - connection from user `alice` and source `198.51.100.10` -> allowed by this rule set (no match)
 ## replay_check_len
  - **Constraints / validation**: `usize`.
  - **Description**: Replay-protection storage length (number of entries tracked for duplicate detection).
@@ -2958,6 +3034,24 @@ If your backend or network is very bandwidth-constrained, reduce cap first. If p
    ```


+## user_rate_limits
+  - **Constraints / validation**: Table `username -> { up_bps, down_bps }`. At least one direction must be non-zero.
+  - **Description**: Per-user bandwidth caps in bytes/sec for upload (`up_bps`) and download (`down_bps`).
+  - **Example**:
+
+    ```toml
+    [access.user_rate_limits]
+    alice = { up_bps = 1048576, down_bps = 2097152 }
+    ```
+## cidr_rate_limits
+  - **Constraints / validation**: Table `CIDR -> { up_bps, down_bps }`. CIDR must parse as `IpNetwork`; at least one direction must be non-zero.
+  - **Description**: Source-subnet bandwidth caps applied alongside per-user limits.
+  - **Example**:
+
+    ```toml
+    [access.cidr_rate_limits]
+    "203.0.113.0/24" = { up_bps = 0, down_bps = 1048576 }
+    ```
 # [[upstreams]]


--- a/docs/Config_params/CONFIG_PARAMS.ru.md
+++ b/docs/Config_params/CONFIG_PARAMS.ru.md
@@ -162,6 +162,8 @@
 | [`log_level`](#log_level) | `"debug"`, `"verbose"`, `"normal"`, or `"silent"` | `"normal"` |
 | [`disable_colors`](#disable_colors) | `bool` | `false` |
 | [`me_socks_kdf_policy`](#me_socks_kdf_policy) | `"strict"` or `"compat"` | `"strict"` |
+| [`me_route_backpressure_enabled`](#me_route_backpressure_enabled) | `bool` | `false` |
+| [`me_route_fairshare_enabled`](#me_route_fairshare_enabled) | `bool` | `false` |
 | [`me_route_backpressure_base_timeout_ms`](#me_route_backpressure_base_timeout_ms) | `u64` | `25` |
 | [`me_route_backpressure_high_timeout_ms`](#me_route_backpressure_high_timeout_ms) | `u64` | `120` |
 | [`me_route_backpressure_high_watermark_pct`](#me_route_backpressure_high_watermark_pct) | `u8` | `80` |
@@ -975,6 +977,24 @@
    [general]
    me_socks_kdf_policy = "strict"
    ```
+## me_route_backpressure_enabled
+  - **Ограничения / валидация**: `bool`.
+  - **Описание**: Включает адаптивные таймауты записи маршрута в зависимости от заполнения канала.
+  - **Example**:
+
+    ```toml
+    [general]
+    me_route_backpressure_enabled = false
+    ```
+## me_route_fairshare_enabled
+  - **Ограничения / валидация**: `bool`.
+  - **Описание**: Включает справедливое распределение нагрузки маршрутизации между writer-потоками.
+  - **Example**:
+
+    ```toml
+    [general]
+    me_route_fairshare_enabled = false
+    ```
 ## me_route_backpressure_base_timeout_ms
  - **Ограничения / валидация**: Должно быть в пределах `1..=5000` (миллисекунд).
  - **Описание**: Базовый таймаут (в миллисекундах) ожидания при режиме **backpressure** (ситуация, при которой данные обрабатываются медленне, чем получаются) для отправки через ME route-channel.
@@ -1755,6 +1775,7 @@
 | [`metrics_whitelist`](#metrics_whitelist) | `IpNetwork[]` | `["127.0.0.1/32", "::1/128"]` |
 | [`max_connections`](#max_connections) | `u32` | `10000` |
 | [`accept_permit_timeout_ms`](#accept_permit_timeout_ms) | `u64` | `250` |
+| [`listen_backlog`](#listen_backlog) | `u32` | `1024` |

 ## port
  - **Ограничения / валидация**: `u16`.
@@ -1765,6 +1786,15 @@
    [server]
    port = 443
    ```
+## listen_backlog
+  - **Ограничения / валидация**: `u32`. `0` использует системный backlog по умолчанию.
+  - **Описание**: Значение backlog, передаваемое в `listen(2)` для TCP-сокетов.
+  - **Example**:
+
+    ```toml
+    [server]
+    listen_backlog = 1024
+    ```
 ## listen_addr_ipv4
  - **Ограничения / валидация**: `String` (необязательный параметр). Если задан, должен содержать валидный IPv4-адрес в формате строки.
  - **Описание**: Прослушиваемый адрес в формате IPv4 (не задавайте этот параметр, если необходимо отключить прослушивание по IPv4).
@@ -2011,6 +2041,7 @@
 | [`runtime_edge_top_n`](#runtime_edge_top_n) | `usize` | `10` |
 | [`runtime_edge_events_capacity`](#runtime_edge_events_capacity) | `usize` | `256` |
 | [`read_only`](#read_only) | `bool` | `false` |
+| [`gray_action`](#gray_action) | `"drop"`, `"api"`, or `"200"` | `"drop"` |

 ## enabled
  - **Ограничения / валидация**: `bool`.
@@ -2021,6 +2052,15 @@
    [server.api]
    enabled = true
    ```
+## gray_action
+  - **Ограничения / валидация**: `"drop"`, `"api"` или `"200"`.
+  - **Описание**: Политика ответа API в «серых» (ограниченных) состояниях: сброс, обычный API-ответ, либо `200 OK`.
+  - **Example**:
+
+    ```toml
+    [server.api]
+    gray_action = "drop"
+    ```
 ## listen
  - **Ограничения / валидация**: `String`. Должно быть в формате `IP:PORT`.
  - **Описание**: Адрес биндинга API в формате `IP:PORT`.
@@ -2213,6 +2253,15 @@
    [timeouts]
    client_handshake = 30
    ```
+## client_first_byte_idle_secs
+  - **Ограничения / валидация**: `u64` (секунды). `0` отключает проверку простоя до первого байта.
+  - **Описание**: Максимальное время ожидания первого байта полезной нагрузки от клиента после установления сессии.
+  - **Example**:
+
+    ```toml
+    [timeouts]
+    client_first_byte_idle_secs = 300
+    ```
 ## relay_idle_policy_v2_enabled
  - **Ограничения / валидация**: `bool`.
  - **Описание**: Включает политику простоя клиента для промежуточного узла.
@@ -2317,6 +2366,7 @@
 | [`server_hello_delay_max_ms`](#server_hello_delay_max_ms) | `u64` | `0` |
 | [`tls_new_session_tickets`](#tls_new_session_tickets) | `u8` | `0` |
 | [`tls_full_cert_ttl_secs`](#tls_full_cert_ttl_secs) | `u64` | `90` |
+| [`serverhello_compact`](#serverhello_compact) | `bool` | `false` |
 | [`alpn_enforce`](#alpn_enforce) | `bool` | `true` |
 | [`mask_proxy_protocol`](#mask_proxy_protocol) | `u8` | `0` |
 | [`mask_shape_hardening`](#mask_shape_hardening) | `bool` | `true` |
@@ -2493,6 +2543,15 @@
    [censorship]
    tls_full_cert_ttl_secs = 90
    ```
+## serverhello_compact
+  - **Ограничения / валидация**: `bool`.
+  - **Описание**: Включает компактный профиль ServerHello/Fake-TLS для снижения сигнатуры размера ответа.
+  - **Example**:
+
+    ```toml
+    [censorship]
+    serverhello_compact = false
+    ```
 ## alpn_enforce
  - **Ограничения / валидация**: `bool`.
  - **Описание**: Принудительно изменяет поведение возврата ALPN в соответствии с предпочтениями клиента.
@@ -2837,6 +2896,8 @@
 | [`replay_check_len`](#replay_check_len) | `usize` | `65536` |
 | [`replay_window_secs`](#replay_window_secs) | `u64` | `120` |
 | [`ignore_time_skew`](#ignore_time_skew) | `bool` | `false` |
+| [`user_rate_limits`](#user_rate_limits) | `Map<String, RateLimitBps>` | `{}` |
+| [`cidr_rate_limits`](#cidr_rate_limits) | `Map<IpNetwork, RateLimitBps>` | `{}` |

 ## users
  - **Ограничения / валидация**: Не должно быть пустым (должен существовать хотя бы один пользователь). Каждое значение должно состоять **ровно из 32 шестнадцатеричных символов**.
@@ -2965,6 +3026,24 @@
    ```


+## user_rate_limits
+  - **Ограничения / валидация**: Таблица `username -> { up_bps, down_bps }`. Должно быть ненулевое значение хотя бы в одном направлении.
+  - **Описание**: Персональные лимиты скорости по пользователям в байтах/сек для отправки (`up_bps`) и получения (`down_bps`).
+  - **Example**:
+
+    ```toml
+    [access.user_rate_limits]
+    alice = { up_bps = 1048576, down_bps = 2097152 }
+    ```
+## cidr_rate_limits
+  - **Ограничения / валидация**: Таблица `CIDR -> { up_bps, down_bps }`. CIDR должен корректно разбираться как `IpNetwork`; хотя бы одно направление должно быть ненулевым.
+  - **Описание**: Лимиты скорости для подсетей источников, применяются поверх пользовательских ограничений.
+  - **Example**:
+
+    ```toml
+    [access.cidr_rate_limits]
+    "203.0.113.0/24" = { up_bps = 0, down_bps = 1048576 }
+    ```
 # [[upstreams]]


--- a/docs/Quick_start/QUICK_START_GUIDE.en.md
+++ b/docs/Quick_start/QUICK_START_GUIDE.en.md
@@ -254,6 +254,19 @@ docker compose down
 > - `docker-compose.yml` maps `./config.toml` to `/app/config.toml` (read-only)
 > - By default it publishes `443:443` and runs with dropped capabilities (only `NET_BIND_SERVICE` is added)
 > - If you really need host networking (usually only for some IPv6 setups) uncomment `network_mode: host`
+> - If you enable mutating Control API endpoints, mount a writable config directory instead of a single `config.toml` file. Telemt persists config changes with atomic `tmp + rename` writes, and a single bind-mounted file can fail with `Device or resource busy`.
+
+Example writable config mount for Control API mutations:
+```yaml
+services:
+  telemt:
+    working_dir: /run/telemt
+    volumes:
+      - ./config:/etc/telemt:rw
+    tmpfs:
+      - /run/telemt:rw,mode=1777,size=4m
+    command: /usr/local/bin/telemt /etc/telemt/config.toml
+```

 **Run without Compose**
 ```bash
--- a/docs/Quick_start/QUICK_START_GUIDE.ru.md
+++ b/docs/Quick_start/QUICK_START_GUIDE.ru.md
@@ -164,7 +164,7 @@ tls_front_dir = "tlsfront"   # Директория кэша для эмуляц
 hello = "00000000000000000000000000000000"
 ```

-Затем нажмите Ctrl+S -> Ctrl+X, чтобы сохранить
+Затем нажмите Ctrl+O -> Ctrl+X, чтобы сохранить

 > [!WARNING]
 > Замените значение параметра `hello` на значение, которое вы получили в пункте 0.  
--- a/install.sh
+++ b/install.sh
@@ -27,6 +27,8 @@ ACTION="install"
 TARGET_VERSION="${VERSION:-latest}"
 LANG_CHOICE="en"

+PATH="${PATH}:/usr/sbin:/sbin"
+
 set_language() {
    case "$1" in
        ru)
@@ -102,6 +104,7 @@ set_language() {
            L_OUT_SUCC_H="УСТАНОВКА УСПЕШНО ЗАВЕРШЕНА"
            L_OUT_UNINST_H="УДАЛЕНИЕ ЗАВЕРШЕНО"
            L_OUT_LINK="Ваша ссылка для подключения к Telegram Proxy:\n"
+            L_ERR_INCORR_ROOT_LOGIN="Используйте 'su -' или 'sudo -i' для входа под пользователем root"
            ;;
        *)
            L_ERR_DOMAIN_REQ="requires a domain argument."
@@ -176,6 +179,7 @@ set_language() {
            L_OUT_SUCC_H="INSTALLATION SUCCESS"
            L_OUT_UNINST_H="UNINSTALLATION COMPLETE"
            L_OUT_LINK="Your Telegram Proxy connection link:\n"
+            L_ERR_INCORR_ROOT_LOGIN="Use 'su -' or 'sudo -i' to login under root"
            ;;
    esac
 }
@@ -388,6 +392,9 @@ verify_common() {

    if [ "$(id -u)" -eq 0 ]; then
        SUDO=""
+        if [ "$(id -u)" -ne 0 ]; then
+            die "$L_ERR_INCORR_ROOT_LOGIN"
+        fi
    else
        command -v sudo >/dev/null 2>&1 || die "$L_ERR_ROOT"
        SUDO="sudo"
--- a/src/api/config_store.rs
+++ b/src/api/config_store.rs
@@ -7,7 +7,7 @@ use hyper::header::IF_MATCH;
 use serde::Serialize;
 use sha2::{Digest, Sha256};

-use crate::config::ProxyConfig;
+use crate::config::{ProxyConfig, RateLimitBps};

 use super::model::ApiFailure;

@@ -18,6 +18,7 @@ pub(super) enum AccessSection {
    UserMaxTcpConns,
    UserExpirations,
    UserDataQuota,
+    UserRateLimits,
    UserMaxUniqueIps,
 }

@@ -29,6 +30,7 @@ impl AccessSection {
            Self::UserMaxTcpConns => "access.user_max_tcp_conns",
            Self::UserExpirations => "access.user_expirations",
            Self::UserDataQuota => "access.user_data_quota",
+            Self::UserRateLimits => "access.user_rate_limits",
            Self::UserMaxUniqueIps => "access.user_max_unique_ips",
        }
    }
@@ -82,6 +84,7 @@ pub(super) async fn load_config_from_disk(config_path: &Path) -> Result<ProxyCon
        .map_err(|e| ApiFailure::internal(format!("failed to load config: {}", e)))
 }

+#[allow(dead_code)]
 pub(super) async fn save_config_to_disk(
    config_path: &Path,
    cfg: &ProxyConfig,
@@ -106,6 +109,12 @@ pub(super) async fn save_access_sections_to_disk(
        if applied.contains(section) {
            continue;
        }
+        if find_toml_table_bounds(&content, section.table_name()).is_none()
+            && access_section_is_empty(cfg, *section)
+        {
+            applied.push(*section);
+            continue;
+        }
        let rendered = render_access_section(cfg, *section)?;
        content = upsert_toml_table(&content, section.table_name(), &rendered);
        applied.push(*section);
@@ -162,6 +171,15 @@ fn render_access_section(cfg: &ProxyConfig, section: AccessSection) -> Result<St
                .collect();
            serialize_table_body(&rows)?
        }
+        AccessSection::UserRateLimits => {
+            let rows: BTreeMap<String, RateLimitBps> = cfg
+                .access
+                .user_rate_limits
+                .iter()
+                .map(|(key, value)| (key.clone(), *value))
+                .collect();
+            serialize_rate_limit_body(&rows)?
+        }
        AccessSection::UserMaxUniqueIps => {
            let rows: BTreeMap<String, usize> = cfg
                .access
@@ -183,11 +201,45 @@ fn render_access_section(cfg: &ProxyConfig, section: AccessSection) -> Result<St
    Ok(out)
 }

+fn access_section_is_empty(cfg: &ProxyConfig, section: AccessSection) -> bool {
+    match section {
+        AccessSection::Users => cfg.access.users.is_empty(),
+        AccessSection::UserAdTags => cfg.access.user_ad_tags.is_empty(),
+        AccessSection::UserMaxTcpConns => cfg.access.user_max_tcp_conns.is_empty(),
+        AccessSection::UserExpirations => cfg.access.user_expirations.is_empty(),
+        AccessSection::UserDataQuota => cfg.access.user_data_quota.is_empty(),
+        AccessSection::UserRateLimits => cfg.access.user_rate_limits.is_empty(),
+        AccessSection::UserMaxUniqueIps => cfg.access.user_max_unique_ips.is_empty(),
+    }
+}
+
 fn serialize_table_body<T: Serialize>(value: &T) -> Result<String, ApiFailure> {
    toml::to_string(value)
        .map_err(|e| ApiFailure::internal(format!("failed to serialize access section: {}", e)))
 }

+fn serialize_rate_limit_body(rows: &BTreeMap<String, RateLimitBps>) -> Result<String, ApiFailure> {
+    let mut out = String::new();
+    for (key, value) in rows {
+        let key = serialize_toml_key(key)?;
+        out.push_str(&format!(
+            "{key} = {{ up_bps = {}, down_bps = {} }}\n",
+            value.up_bps, value.down_bps
+        ));
+    }
+    Ok(out)
+}
+
+fn serialize_toml_key(key: &str) -> Result<String, ApiFailure> {
+    let mut row = BTreeMap::new();
+    row.insert(key.to_string(), 0_u8);
+    let rendered = serialize_table_body(&row)?;
+    rendered
+        .split_once(" = ")
+        .map(|(key, _)| key.to_string())
+        .ok_or_else(|| ApiFailure::internal("failed to serialize TOML key"))
+}
+
 fn upsert_toml_table(source: &str, table_name: &str, replacement: &str) -> String {
    if let Some((start, end)) = find_toml_table_bounds(source, table_name) {
        let mut out = String::with_capacity(source.len() + replacement.len());
@@ -267,3 +319,26 @@ fn write_atomic_sync(path: &Path, contents: &str) -> std::io::Result<()> {
    }
    write_result
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn render_user_rate_limits_section() {
+        let mut cfg = ProxyConfig::default();
+        cfg.access.user_rate_limits.insert(
+            "alice".to_string(),
+            RateLimitBps {
+                up_bps: 1024,
+                down_bps: 2048,
+            },
+        );
+
+        let rendered = render_access_section(&cfg, AccessSection::UserRateLimits)
+            .expect("section must render");
+
+        assert!(rendered.starts_with("[access.user_rate_limits]\n"));
+        assert!(rendered.contains("alice = { up_bps = 1024, down_bps = 2048 }"));
+    }
+}
--- a/src/api/mod.rs
+++ b/src/api/mod.rs
@@ -5,6 +5,7 @@ use std::net::{IpAddr, SocketAddr};
 use std::path::PathBuf;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
+use std::time::Duration;

 use http_body_util::Full;
 use hyper::body::{Bytes, Incoming};
@@ -12,8 +13,10 @@ use hyper::header::AUTHORIZATION;
 use hyper::server::conn::http1;
 use hyper::service::service_fn;
 use hyper::{Method, Request, Response, StatusCode};
+use subtle::ConstantTimeEq;
 use tokio::net::TcpListener;
-use tokio::sync::{Mutex, RwLock, watch};
+use tokio::sync::{Mutex, RwLock, Semaphore, watch};
+use tokio::time::timeout;
 use tracing::{debug, info, warn};

 use crate::config::{ApiGrayAction, ProxyConfig};
@@ -28,6 +31,7 @@ mod config_store;
 mod events;
 mod http_utils;
 mod model;
+mod patch;
 mod runtime_edge;
 mod runtime_init;
 mod runtime_min;
@@ -42,7 +46,8 @@ use events::ApiEventStore;
 use http_utils::{error_response, read_json, read_optional_json, success_response};
 use model::{
    ApiFailure, ClassCount, CreateUserRequest, DeleteUserResponse, HealthData, HealthReadyData,
-    PatchUserRequest, RotateSecretRequest, SummaryData, UserActiveIps,
+    PatchUserRequest, ResetUserQuotaResponse, RotateSecretRequest, SummaryData, UserActiveIps,
+    is_valid_username,
 };
 use runtime_edge::{
    EdgeConnectionsCacheEntry, build_runtime_connections_summary_data,
@@ -63,7 +68,13 @@ use runtime_zero::{
    build_limits_effective_data, build_runtime_gates_data, build_security_posture_data,
    build_system_info_data,
 };
-use users::{create_user, delete_user, patch_user, rotate_secret, users_from_config};
+use users::{
+    build_user_quota_list, create_user, delete_user, patch_user, rotate_secret, users_from_config,
+};
+
+const API_MAX_CONTROL_CONNECTIONS: usize = 1024;
+const API_HTTP_CONNECTION_TIMEOUT: Duration = Duration::from_secs(15);
+const ROUTE_USERNAME_ERROR: &str = "username must match [A-Za-z0-9_.-] and be 1..64 chars";

 pub(super) struct ApiRuntimeState {
    pub(super) process_started_at_epoch_secs: u64,
@@ -79,6 +90,7 @@ pub(super) struct ApiShared {
    pub(super) me_pool: Arc<RwLock<Option<Arc<MePool>>>>,
    pub(super) upstream_manager: Arc<UpstreamManager>,
    pub(super) config_path: PathBuf,
+    pub(super) quota_state_path: PathBuf,
    pub(super) detected_ips_rx: watch::Receiver<(Option<IpAddr>, Option<IpAddr>)>,
    pub(super) mutation_lock: Arc<Mutex<()>>,
    pub(super) minimal_cache: Arc<Mutex<Option<MinimalCacheEntry>>>,
@@ -101,6 +113,18 @@ impl ApiShared {
    }
 }

+fn auth_header_matches(actual: &str, expected: &str) -> bool {
+    actual.as_bytes().ct_eq(expected.as_bytes()).into()
+}
+
+fn parse_route_username(user: &str) -> Result<&str, ApiFailure> {
+    if is_valid_username(user) {
+        Ok(user)
+    } else {
+        Err(ApiFailure::bad_request(ROUTE_USERNAME_ERROR))
+    }
+}
+
 pub async fn serve(
    listen: SocketAddr,
    stats: Arc<Stats>,
@@ -111,6 +135,7 @@ pub async fn serve(
    config_rx: watch::Receiver<Arc<ProxyConfig>>,
    admission_rx: watch::Receiver<bool>,
    config_path: PathBuf,
+    quota_state_path: PathBuf,
    detected_ips_rx: watch::Receiver<(Option<IpAddr>, Option<IpAddr>)>,
    process_started_at_epoch_secs: u64,
    startup_tracker: Arc<StartupTracker>,
@@ -142,6 +167,7 @@ pub async fn serve(
        me_pool,
        upstream_manager,
        config_path,
+        quota_state_path,
        detected_ips_rx,
        mutation_lock: Arc::new(Mutex::new(())),
        minimal_cache: Arc::new(Mutex::new(None)),
@@ -163,6 +189,8 @@ pub async fn serve(
        shared.runtime_events.clone(),
    );

+    let connection_permits = Arc::new(Semaphore::new(API_MAX_CONTROL_CONNECTIONS));
+
    loop {
        let (stream, peer) = match listener.accept().await {
            Ok(v) => v,
@@ -172,20 +200,45 @@ pub async fn serve(
            }
        };

+        let connection_permit = match connection_permits.clone().try_acquire_owned() {
+            Ok(permit) => permit,
+            Err(_) => {
+                debug!(
+                    peer = %peer,
+                    max_connections = API_MAX_CONTROL_CONNECTIONS,
+                    "Dropping API connection: control-plane connection budget exhausted"
+                );
+                continue;
+            }
+        };
+
        let shared_conn = shared.clone();
        let config_rx_conn = config_rx.clone();
        tokio::spawn(async move {
+            let _connection_permit = connection_permit;
            let svc = service_fn(move |req: Request<Incoming>| {
                let shared_req = shared_conn.clone();
                let config_rx_req = config_rx_conn.clone();
                async move { handle(req, peer, shared_req, config_rx_req).await }
            });
-            if let Err(error) = http1::Builder::new()
-                .serve_connection(hyper_util::rt::TokioIo::new(stream), svc)
-                .await
+            match timeout(
+                API_HTTP_CONNECTION_TIMEOUT,
+                http1::Builder::new().serve_connection(hyper_util::rt::TokioIo::new(stream), svc),
+            )
+            .await
            {
-                if !error.is_user() {
-                    debug!(error = %error, "API connection error");
+                Ok(Ok(())) => {}
+                Ok(Err(error)) => {
+                    if !error.is_user() {
+                        debug!(error = %error, "API connection error");
+                    }
+                }
+                Err(_) => {
+                    debug!(
+                        peer = %peer,
+                        timeout_ms = API_HTTP_CONNECTION_TIMEOUT.as_millis() as u64,
+                        "API connection timed out"
+                    );
                }
            }
        });
@@ -241,7 +294,7 @@ async fn handle(
            .headers()
            .get(AUTHORIZATION)
            .and_then(|v| v.to_str().ok())
-            .map(|v| v == api_cfg.auth_header)
+            .map(|v| auth_header_matches(v, &api_cfg.auth_header))
            .unwrap_or(false);
        if !auth_ok {
            return Ok(error_response(
@@ -453,6 +506,12 @@ async fn handle(
                .await;
                Ok(success_response(StatusCode::OK, users, revision))
            }
+            ("GET", "/v1/users/quota") => {
+                let revision = current_revision(&shared.config_path).await?;
+                let disk_cfg = load_config_from_disk(&shared.config_path).await?;
+                let data = build_user_quota_list(&disk_cfg, shared.stats.as_ref());
+                Ok(success_response(StatusCode::OK, data, revision))
+            }
            ("POST", "/v1/users") => {
                if api_cfg.read_only {
                    return Ok(error_response(
@@ -490,10 +549,115 @@ async fn handle(
                Ok(success_response(status, data, revision))
            }
            _ => {
+                if method == Method::POST
+                    && let Some(user) = normalized_path
+                        .strip_prefix("/v1/users/")
+                        .and_then(|path| path.strip_suffix("/reset-quota"))
+                    && !user.is_empty()
+                    && !user.contains('/')
+                {
+                    let user = parse_route_username(user)?;
+                    if api_cfg.read_only {
+                        return Ok(error_response(
+                            request_id,
+                            ApiFailure::new(
+                                StatusCode::FORBIDDEN,
+                                "read_only",
+                                "API runs in read-only mode",
+                            ),
+                        ));
+                    }
+                    let snapshot = match crate::quota_state::reset_user_quota(
+                        &shared.quota_state_path,
+                        shared.stats.as_ref(),
+                        user,
+                    )
+                    .await
+                    {
+                        Ok(snapshot) => snapshot,
+                        Err(error) => {
+                            shared.runtime_events.record(
+                                "api.user.reset_quota.failed",
+                                format!("username={} error={}", user, error),
+                            );
+                            return Err(ApiFailure::internal(format!(
+                                "Failed to reset user quota: {}",
+                                error
+                            )));
+                        }
+                    };
+                    shared
+                        .runtime_events
+                        .record("api.user.reset_quota.ok", format!("username={}", user));
+                    let revision = current_revision(&shared.config_path).await?;
+                    return Ok(success_response(
+                        StatusCode::OK,
+                        ResetUserQuotaResponse {
+                            username: user.to_string(),
+                            used_bytes: snapshot.used_bytes,
+                            last_reset_epoch_secs: snapshot.last_reset_epoch_secs,
+                        },
+                        revision,
+                    ));
+                }
+                if method == Method::POST
+                    && let Some(base_user) = normalized_path
+                        .strip_prefix("/v1/users/")
+                        .and_then(|path| path.strip_suffix("/rotate-secret"))
+                    && !base_user.is_empty()
+                    && !base_user.contains('/')
+                {
+                    let base_user = parse_route_username(base_user)?;
+                    if api_cfg.read_only {
+                        return Ok(error_response(
+                            request_id,
+                            ApiFailure::new(
+                                StatusCode::FORBIDDEN,
+                                "read_only",
+                                "API runs in read-only mode",
+                            ),
+                        ));
+                    }
+                    let expected_revision = parse_if_match(req.headers());
+                    let body =
+                        read_optional_json::<RotateSecretRequest>(req.into_body(), body_limit)
+                            .await?;
+                    let result = rotate_secret(
+                        base_user,
+                        body.unwrap_or_default(),
+                        expected_revision,
+                        &shared,
+                    )
+                    .await;
+                    let (mut data, revision) = match result {
+                        Ok(ok) => ok,
+                        Err(error) => {
+                            shared.runtime_events.record(
+                                "api.user.rotate_secret.failed",
+                                format!("username={} code={}", base_user, error.code),
+                            );
+                            return Err(error);
+                        }
+                    };
+                    let runtime_cfg = config_rx.borrow().clone();
+                    data.user.in_runtime =
+                        runtime_cfg.access.users.contains_key(&data.user.username);
+                    shared.runtime_events.record(
+                        "api.user.rotate_secret.ok",
+                        format!("username={}", base_user),
+                    );
+                    let status = if data.user.in_runtime {
+                        StatusCode::OK
+                    } else {
+                        StatusCode::ACCEPTED
+                    };
+                    return Ok(success_response(status, data, revision));
+                }
                if let Some(user) = normalized_path.strip_prefix("/v1/users/")
                    && !user.is_empty()
                    && !user.contains('/')
                {
+                    let user = parse_route_username(user)?;
                    if method == Method::GET {
                        let revision = current_revision(&shared.config_path).await?;
                        let disk_cfg = load_config_from_disk(&shared.config_path).await?;
@@ -594,56 +758,6 @@ async fn handle(
                        };
                        return Ok(success_response(status, response, revision));
                    }
-                    if method == Method::POST
-                        && let Some(base_user) = user.strip_suffix("/rotate-secret")
-                        && !base_user.is_empty()
-                        && !base_user.contains('/')
-                    {
-                        if api_cfg.read_only {
-                            return Ok(error_response(
-                                request_id,
-                                ApiFailure::new(
-                                    StatusCode::FORBIDDEN,
-                                    "read_only",
-                                    "API runs in read-only mode",
-                                ),
-                            ));
-                        }
-                        let expected_revision = parse_if_match(req.headers());
-                        let body =
-                            read_optional_json::<RotateSecretRequest>(req.into_body(), body_limit)
-                                .await?;
-                        let result = rotate_secret(
-                            base_user,
-                            body.unwrap_or_default(),
-                            expected_revision,
-                            &shared,
-                        )
-                        .await;
-                        let (mut data, revision) = match result {
-                            Ok(ok) => ok,
-                            Err(error) => {
-                                shared.runtime_events.record(
-                                    "api.user.rotate_secret.failed",
-                                    format!("username={} code={}", base_user, error.code),
-                                );
-                                return Err(error);
-                            }
-                        };
-                        let runtime_cfg = config_rx.borrow().clone();
-                        data.user.in_runtime =
-                            runtime_cfg.access.users.contains_key(&data.user.username);
-                        shared.runtime_events.record(
-                            "api.user.rotate_secret.ok",
-                            format!("username={}", base_user),
-                        );
-                        let status = if data.user.in_runtime {
-                            StatusCode::OK
-                        } else {
-                            StatusCode::ACCEPTED
-                        };
-                        return Ok(success_response(status, data, revision));
-                    }
                    if method == Method::POST {
                        return Ok(error_response(
                            request_id,
--- a/src/api/model.rs
+++ b/src/api/model.rs
@@ -5,6 +5,7 @@ use chrono::{DateTime, Utc};
 use hyper::StatusCode;
 use serde::{Deserialize, Serialize};

+use super::patch::{Patch, patch_field};
 use crate::crypto::SecureRandom;

 const MAX_USERNAME_LEN: usize = 64;
@@ -455,6 +456,13 @@ pub(super) struct UserLinks {
    pub(super) classic: Vec<String>,
    pub(super) secure: Vec<String>,
    pub(super) tls: Vec<String>,
+    pub(super) tls_domains: Vec<TlsDomainLink>,
+}
+
+#[derive(Serialize)]
+pub(super) struct TlsDomainLink {
+    pub(super) domain: String,
+    pub(super) link: String,
 }

 #[derive(Serialize)]
@@ -465,6 +473,8 @@ pub(super) struct UserInfo {
    pub(super) max_tcp_conns: Option<usize>,
    pub(super) expiration_rfc3339: Option<String>,
    pub(super) data_quota_bytes: Option<u64>,
+    pub(super) rate_limit_up_bps: Option<u64>,
+    pub(super) rate_limit_down_bps: Option<u64>,
    pub(super) max_unique_ips: Option<usize>,
    pub(super) current_connections: u64,
    pub(super) active_unique_ips: usize,
@@ -493,6 +503,26 @@ pub(super) struct DeleteUserResponse {
    pub(super) in_runtime: bool,
 }

+#[derive(Serialize)]
+pub(super) struct ResetUserQuotaResponse {
+    pub(super) username: String,
+    pub(super) used_bytes: u64,
+    pub(super) last_reset_epoch_secs: u64,
+}
+
+#[derive(Serialize)]
+pub(super) struct UserQuotaListData {
+    pub(super) users: Vec<UserQuotaEntry>,
+}
+
+#[derive(Serialize)]
+pub(super) struct UserQuotaEntry {
+    pub(super) username: String,
+    pub(super) data_quota_bytes: u64,
+    pub(super) used_bytes: u64,
+    pub(super) last_reset_epoch_secs: u64,
+}
+
 #[derive(Deserialize)]
 pub(super) struct CreateUserRequest {
    pub(super) username: String,
@@ -501,17 +531,28 @@ pub(super) struct CreateUserRequest {
    pub(super) max_tcp_conns: Option<usize>,
    pub(super) expiration_rfc3339: Option<String>,
    pub(super) data_quota_bytes: Option<u64>,
+    pub(super) rate_limit_up_bps: Option<u64>,
+    pub(super) rate_limit_down_bps: Option<u64>,
    pub(super) max_unique_ips: Option<usize>,
 }

 #[derive(Deserialize)]
 pub(super) struct PatchUserRequest {
    pub(super) secret: Option<String>,
-    pub(super) user_ad_tag: Option<String>,
-    pub(super) max_tcp_conns: Option<usize>,
-    pub(super) expiration_rfc3339: Option<String>,
-    pub(super) data_quota_bytes: Option<u64>,
-    pub(super) max_unique_ips: Option<usize>,
+    #[serde(default, deserialize_with = "patch_field")]
+    pub(super) user_ad_tag: Patch<String>,
+    #[serde(default, deserialize_with = "patch_field")]
+    pub(super) max_tcp_conns: Patch<usize>,
+    #[serde(default, deserialize_with = "patch_field")]
+    pub(super) expiration_rfc3339: Patch<String>,
+    #[serde(default, deserialize_with = "patch_field")]
+    pub(super) data_quota_bytes: Patch<u64>,
+    #[serde(default, deserialize_with = "patch_field")]
+    pub(super) rate_limit_up_bps: Patch<u64>,
+    #[serde(default, deserialize_with = "patch_field")]
+    pub(super) rate_limit_down_bps: Patch<u64>,
+    #[serde(default, deserialize_with = "patch_field")]
+    pub(super) max_unique_ips: Patch<usize>,
 }

 #[derive(Default, Deserialize)]
@@ -530,6 +571,20 @@ pub(super) fn parse_optional_expiration(
    Ok(Some(parsed.with_timezone(&Utc)))
 }

+pub(super) fn parse_patch_expiration(
+    value: &Patch<String>,
+) -> Result<Patch<DateTime<Utc>>, ApiFailure> {
+    match value {
+        Patch::Unchanged => Ok(Patch::Unchanged),
+        Patch::Remove => Ok(Patch::Remove),
+        Patch::Set(raw) => {
+            let parsed = DateTime::parse_from_rfc3339(raw)
+                .map_err(|_| ApiFailure::bad_request("expiration_rfc3339 must be valid RFC3339"))?;
+            Ok(Patch::Set(parsed.with_timezone(&Utc)))
+        }
+    }
+}
+
 pub(super) fn is_valid_user_secret(secret: &str) -> bool {
    secret.len() == 32 && secret.chars().all(|c| c.is_ascii_hexdigit())
 }
--- a/src/api/patch.rs
+++ b/src/api/patch.rs
@@ -0,0 +1,134 @@
+use serde::Deserialize;
+
+/// Three-state field for JSON Merge Patch semantics on the `PATCH /v1/users/{user}`
+/// endpoint.
+///
+/// `Unchanged` is produced when the JSON body omits the field entirely and tells the
+/// handler to leave the corresponding configuration entry untouched. `Remove` is
+/// produced when the JSON body sets the field to `null` and instructs the handler to
+/// drop the entry from the corresponding access HashMap. `Set` carries an explicit
+/// new value, including zero, which is preserved verbatim in the configuration.
+#[derive(Debug)]
+pub(super) enum Patch<T> {
+    Unchanged,
+    Remove,
+    Set(T),
+}
+
+impl<T> Default for Patch<T> {
+    fn default() -> Self {
+        Self::Unchanged
+    }
+}
+
+/// Serde deserializer adapter for fields that follow JSON Merge Patch semantics.
+///
+/// Pair this with `#[serde(default, deserialize_with = "patch_field")]` on a
+/// `Patch<T>` field. An omitted field falls back to `Patch::Unchanged` via
+/// `Default`; an explicit JSON `null` becomes `Patch::Remove`; any other value
+/// becomes `Patch::Set(v)`.
+pub(super) fn patch_field<'de, D, T>(deserializer: D) -> Result<Patch<T>, D::Error>
+where
+    D: serde::Deserializer<'de>,
+    T: serde::Deserialize<'de>,
+{
+    Option::<T>::deserialize(deserializer).map(|opt| match opt {
+        Some(value) => Patch::Set(value),
+        None => Patch::Remove,
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::api::model::{PatchUserRequest, parse_patch_expiration};
+    use chrono::{TimeZone, Utc};
+    use serde::Deserialize;
+
+    #[derive(Deserialize)]
+    struct Holder {
+        #[serde(default, deserialize_with = "patch_field")]
+        value: Patch<u64>,
+    }
+
+    fn parse(json: &str) -> Holder {
+        serde_json::from_str(json).expect("valid json")
+    }
+
+    #[test]
+    fn omitted_field_yields_unchanged() {
+        let h = parse("{}");
+        assert!(matches!(h.value, Patch::Unchanged));
+    }
+
+    #[test]
+    fn explicit_null_yields_remove() {
+        let h = parse(r#"{"value": null}"#);
+        assert!(matches!(h.value, Patch::Remove));
+    }
+
+    #[test]
+    fn explicit_value_yields_set() {
+        let h = parse(r#"{"value": 42}"#);
+        assert!(matches!(h.value, Patch::Set(42)));
+    }
+
+    #[test]
+    fn explicit_zero_yields_set_zero() {
+        let h = parse(r#"{"value": 0}"#);
+        assert!(matches!(h.value, Patch::Set(0)));
+    }
+
+    #[test]
+    fn parse_patch_expiration_passes_unchanged_and_remove_through() {
+        assert!(matches!(
+            parse_patch_expiration(&Patch::Unchanged),
+            Ok(Patch::Unchanged)
+        ));
+        assert!(matches!(
+            parse_patch_expiration(&Patch::Remove),
+            Ok(Patch::Remove)
+        ));
+    }
+
+    #[test]
+    fn parse_patch_expiration_parses_set_value() {
+        let parsed =
+            parse_patch_expiration(&Patch::Set("2030-01-02T03:04:05Z".into())).expect("valid");
+        match parsed {
+            Patch::Set(dt) => {
+                assert_eq!(dt, Utc.with_ymd_and_hms(2030, 1, 2, 3, 4, 5).unwrap());
+            }
+            other => panic!("expected Patch::Set, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn parse_patch_expiration_rejects_invalid_set_value() {
+        assert!(parse_patch_expiration(&Patch::Set("not-a-date".into())).is_err());
+    }
+
+    #[test]
+    fn patch_user_request_deserializes_mixed_states() {
+        let raw = r#"{
+            "secret": "00112233445566778899aabbccddeeff",
+            "max_tcp_conns": 0,
+            "max_unique_ips": null,
+            "data_quota_bytes": 1024,
+            "rate_limit_up_bps": 4096,
+            "rate_limit_down_bps": null
+        }"#;
+        let req: PatchUserRequest = serde_json::from_str(raw).expect("valid json");
+        assert_eq!(
+            req.secret.as_deref(),
+            Some("00112233445566778899aabbccddeeff")
+        );
+        assert!(matches!(req.max_tcp_conns, Patch::Set(0)));
+        assert!(matches!(req.max_unique_ips, Patch::Remove));
+        assert!(matches!(req.data_quota_bytes, Patch::Set(1024)));
+        assert!(matches!(req.rate_limit_up_bps, Patch::Set(4096)));
+        assert!(matches!(req.rate_limit_down_bps, Patch::Remove));
+        assert!(matches!(req.expiration_rfc3339, Patch::Unchanged));
+        assert!(matches!(req.user_ad_tag, Patch::Unchanged));
+    }
+}
--- a/src/api/users.rs
+++ b/src/api/users.rs
@@ -3,19 +3,22 @@ use std::net::IpAddr;
 use hyper::StatusCode;

 use crate::config::ProxyConfig;
+use crate::config::RateLimitBps;
 use crate::ip_tracker::UserIpTracker;
 use crate::stats::Stats;

 use super::ApiShared;
 use super::config_store::{
-    AccessSection, ensure_expected_revision, load_config_from_disk, save_access_sections_to_disk,
-    save_config_to_disk,
+    AccessSection, current_revision, ensure_expected_revision, load_config_from_disk,
+    save_access_sections_to_disk,
 };
 use super::model::{
    ApiFailure, CreateUserRequest, CreateUserResponse, PatchUserRequest, RotateSecretRequest,
-    UserInfo, UserLinks, is_valid_ad_tag, is_valid_user_secret, is_valid_username,
-    parse_optional_expiration, random_user_secret,
+    TlsDomainLink, UserInfo, UserLinks, UserQuotaEntry, UserQuotaListData, is_valid_ad_tag,
+    is_valid_user_secret, is_valid_username, parse_optional_expiration, parse_patch_expiration,
+    random_user_secret,
 };
+use super::patch::Patch;

 pub(super) async fn create_user(
    body: CreateUserRequest,
@@ -26,6 +29,8 @@ pub(super) async fn create_user(
    let touches_user_max_tcp_conns = body.max_tcp_conns.is_some();
    let touches_user_expirations = body.expiration_rfc3339.is_some();
    let touches_user_data_quota = body.data_quota_bytes.is_some();
+    let touches_user_rate_limits =
+        body.rate_limit_up_bps.is_some() || body.rate_limit_down_bps.is_some();
    let touches_user_max_unique_ips = body.max_unique_ips.is_some();

    if !is_valid_username(&body.username) {
@@ -90,6 +95,15 @@ pub(super) async fn create_user(
            .user_data_quota
            .insert(body.username.clone(), quota);
    }
+    if touches_user_rate_limits {
+        cfg.access.user_rate_limits.insert(
+            body.username.clone(),
+            RateLimitBps {
+                up_bps: body.rate_limit_up_bps.unwrap_or(0),
+                down_bps: body.rate_limit_down_bps.unwrap_or(0),
+            },
+        );
+    }

    let updated_limit = body.max_unique_ips;
    if let Some(limit) = updated_limit {
@@ -114,6 +128,9 @@ pub(super) async fn create_user(
    if touches_user_data_quota {
        touched_sections.push(AccessSection::UserDataQuota);
    }
+    if touches_user_rate_limits {
+        touched_sections.push(AccessSection::UserRateLimits);
+    }
    if touches_user_max_unique_ips {
        touched_sections.push(AccessSection::UserMaxUniqueIps);
    }
@@ -156,6 +173,8 @@ pub(super) async fn create_user(
                    .then_some(cfg.access.user_max_tcp_conns_global_each)),
            expiration_rfc3339: None,
            data_quota_bytes: None,
+            rate_limit_up_bps: body.rate_limit_up_bps.filter(|limit| *limit > 0),
+            rate_limit_down_bps: body.rate_limit_down_bps.filter(|limit| *limit > 0),
            max_unique_ips: updated_limit,
            current_connections: 0,
            active_unique_ips: 0,
@@ -175,6 +194,15 @@ pub(super) async fn patch_user(
    expected_revision: Option<String>,
    shared: &ApiShared,
 ) -> Result<(UserInfo, String), ApiFailure> {
+    let touches_users = body.secret.is_some();
+    let touches_user_ad_tags = !matches!(&body.user_ad_tag, Patch::Unchanged);
+    let touches_user_max_tcp_conns = !matches!(&body.max_tcp_conns, Patch::Unchanged);
+    let touches_user_expirations = !matches!(&body.expiration_rfc3339, Patch::Unchanged);
+    let touches_user_data_quota = !matches!(&body.data_quota_bytes, Patch::Unchanged);
+    let touches_user_rate_limits = !matches!(&body.rate_limit_up_bps, Patch::Unchanged)
+        || !matches!(&body.rate_limit_down_bps, Patch::Unchanged);
+    let touches_user_max_unique_ips = !matches!(&body.max_unique_ips, Patch::Unchanged);
+
    if let Some(secret) = body.secret.as_ref()
        && !is_valid_user_secret(secret)
    {
@@ -182,14 +210,14 @@ pub(super) async fn patch_user(
            "secret must be exactly 32 hex characters",
        ));
    }
-    if let Some(ad_tag) = body.user_ad_tag.as_ref()
+    if let Patch::Set(ad_tag) = &body.user_ad_tag
        && !is_valid_ad_tag(ad_tag)
    {
        return Err(ApiFailure::bad_request(
            "user_ad_tag must be exactly 32 hex characters",
        ));
    }
-    let expiration = parse_optional_expiration(body.expiration_rfc3339.as_deref())?;
+    let expiration = parse_patch_expiration(&body.expiration_rfc3339)?;
    let _guard = shared.mutation_lock.lock().await;
    let mut cfg = load_config_from_disk(&shared.config_path).await?;
    ensure_expected_revision(&shared.config_path, expected_revision.as_deref()).await?;
@@ -205,38 +233,123 @@ pub(super) async fn patch_user(
    if let Some(secret) = body.secret {
        cfg.access.users.insert(user.to_string(), secret);
    }
-    if let Some(ad_tag) = body.user_ad_tag {
-        cfg.access.user_ad_tags.insert(user.to_string(), ad_tag);
+    match body.user_ad_tag {
+        Patch::Unchanged => {}
+        Patch::Remove => {
+            cfg.access.user_ad_tags.remove(user);
+        }
+        Patch::Set(ad_tag) => {
+            cfg.access.user_ad_tags.insert(user.to_string(), ad_tag);
+        }
    }
-    if let Some(limit) = body.max_tcp_conns {
-        cfg.access
-            .user_max_tcp_conns
-            .insert(user.to_string(), limit);
+    match body.max_tcp_conns {
+        Patch::Unchanged => {}
+        Patch::Remove => {
+            cfg.access.user_max_tcp_conns.remove(user);
+        }
+        Patch::Set(limit) => {
+            cfg.access
+                .user_max_tcp_conns
+                .insert(user.to_string(), limit);
+        }
    }
-    if let Some(expiration) = expiration {
-        cfg.access
-            .user_expirations
-            .insert(user.to_string(), expiration);
+    match expiration {
+        Patch::Unchanged => {}
+        Patch::Remove => {
+            cfg.access.user_expirations.remove(user);
+        }
+        Patch::Set(expiration) => {
+            cfg.access
+                .user_expirations
+                .insert(user.to_string(), expiration);
+        }
    }
-    if let Some(quota) = body.data_quota_bytes {
-        cfg.access.user_data_quota.insert(user.to_string(), quota);
+    match body.data_quota_bytes {
+        Patch::Unchanged => {}
+        Patch::Remove => {
+            cfg.access.user_data_quota.remove(user);
+        }
+        Patch::Set(quota) => {
+            cfg.access.user_data_quota.insert(user.to_string(), quota);
+        }
    }
-
-    let mut updated_limit = None;
-    if let Some(limit) = body.max_unique_ips {
-        cfg.access
-            .user_max_unique_ips
-            .insert(user.to_string(), limit);
-        updated_limit = Some(limit);
+    if touches_user_rate_limits {
+        let mut rate_limit = cfg
+            .access
+            .user_rate_limits
+            .get(user)
+            .copied()
+            .unwrap_or_default();
+        match body.rate_limit_up_bps {
+            Patch::Unchanged => {}
+            Patch::Remove => rate_limit.up_bps = 0,
+            Patch::Set(limit) => rate_limit.up_bps = limit,
+        }
+        match body.rate_limit_down_bps {
+            Patch::Unchanged => {}
+            Patch::Remove => rate_limit.down_bps = 0,
+            Patch::Set(limit) => rate_limit.down_bps = limit,
+        }
+        if rate_limit.up_bps == 0 && rate_limit.down_bps == 0 {
+            cfg.access.user_rate_limits.remove(user);
+        } else {
+            cfg.access
+                .user_rate_limits
+                .insert(user.to_string(), rate_limit);
+        }
    }
+    // Capture how the per-user IP limit changed, so the in-memory ip_tracker
+    // can be synced (set or removed) after the config is persisted.
+    let max_unique_ips_change = match body.max_unique_ips {
+        Patch::Unchanged => None,
+        Patch::Remove => {
+            cfg.access.user_max_unique_ips.remove(user);
+            Some(None)
+        }
+        Patch::Set(limit) => {
+            cfg.access
+                .user_max_unique_ips
+                .insert(user.to_string(), limit);
+            Some(Some(limit))
+        }
+    };

    cfg.validate()
        .map_err(|e| ApiFailure::bad_request(format!("config validation failed: {}", e)))?;

-    let revision = save_config_to_disk(&shared.config_path, &cfg).await?;
+    let mut touched_sections = Vec::new();
+    if touches_users {
+        touched_sections.push(AccessSection::Users);
+    }
+    if touches_user_ad_tags {
+        touched_sections.push(AccessSection::UserAdTags);
+    }
+    if touches_user_max_tcp_conns {
+        touched_sections.push(AccessSection::UserMaxTcpConns);
+    }
+    if touches_user_expirations {
+        touched_sections.push(AccessSection::UserExpirations);
+    }
+    if touches_user_data_quota {
+        touched_sections.push(AccessSection::UserDataQuota);
+    }
+    if touches_user_rate_limits {
+        touched_sections.push(AccessSection::UserRateLimits);
+    }
+    if touches_user_max_unique_ips {
+        touched_sections.push(AccessSection::UserMaxUniqueIps);
+    }
+
+    let revision = if touched_sections.is_empty() {
+        current_revision(&shared.config_path).await?
+    } else {
+        save_access_sections_to_disk(&shared.config_path, &cfg, &touched_sections).await?
+    };
    drop(_guard);
-    if let Some(limit) = updated_limit {
-        shared.ip_tracker.set_user_limit(user, limit).await;
+    match max_unique_ips_change {
+        Some(Some(limit)) => shared.ip_tracker.set_user_limit(user, limit).await,
+        Some(None) => shared.ip_tracker.remove_user_limit(user).await,
+        None => {}
    }
    let (detected_ip_v4, detected_ip_v6) = shared.detected_link_ips();
    let users = users_from_config(
@@ -290,6 +403,7 @@ pub(super) async fn rotate_secret(
        AccessSection::UserMaxTcpConns,
        AccessSection::UserExpirations,
        AccessSection::UserDataQuota,
+        AccessSection::UserRateLimits,
        AccessSection::UserMaxUniqueIps,
    ];
    let revision =
@@ -349,6 +463,7 @@ pub(super) async fn delete_user(
    cfg.access.user_max_tcp_conns.remove(user);
    cfg.access.user_expirations.remove(user);
    cfg.access.user_data_quota.remove(user);
+    cfg.access.user_rate_limits.remove(user);
    cfg.access.user_max_unique_ips.remove(user);

    cfg.validate()
@@ -359,6 +474,7 @@ pub(super) async fn delete_user(
        AccessSection::UserMaxTcpConns,
        AccessSection::UserExpirations,
        AccessSection::UserDataQuota,
+        AccessSection::UserRateLimits,
        AccessSection::UserMaxUniqueIps,
    ];
    let revision =
@@ -400,11 +516,7 @@ pub(super) async fn users_from_config(
            .map(|secret| {
                build_user_links(cfg, secret, startup_detected_ip_v4, startup_detected_ip_v6)
            })
-            .unwrap_or(UserLinks {
-                classic: Vec::new(),
-                secure: Vec::new(),
-                tls: Vec::new(),
-            });
+            .unwrap_or_else(empty_user_links);
        users.push(UserInfo {
            in_runtime: runtime_cfg
                .map(|runtime| runtime.access.users.contains_key(&username))
@@ -424,6 +536,18 @@ pub(super) async fn users_from_config(
                .get(&username)
                .map(chrono::DateTime::<chrono::Utc>::to_rfc3339),
            data_quota_bytes: cfg.access.user_data_quota.get(&username).copied(),
+            rate_limit_up_bps: cfg
+                .access
+                .user_rate_limits
+                .get(&username)
+                .map(|limit| limit.up_bps)
+                .filter(|limit| *limit > 0),
+            rate_limit_down_bps: cfg
+                .access
+                .user_rate_limits
+                .get(&username)
+                .map(|limit| limit.down_bps)
+                .filter(|limit| *limit > 0),
            max_unique_ips: cfg
                .access
                .user_max_unique_ips
@@ -445,6 +569,42 @@ pub(super) async fn users_from_config(
    users
 }

+pub(super) fn build_user_quota_list(cfg: &ProxyConfig, stats: &Stats) -> UserQuotaListData {
+    let mut names = cfg.access.users.keys().cloned().collect::<Vec<_>>();
+    names.sort();
+
+    let snapshot = stats.user_quota_snapshot();
+    let mut users = Vec::with_capacity(names.len());
+    for username in names {
+        let Some(&data_quota_bytes) = cfg.access.user_data_quota.get(&username) else {
+            continue;
+        };
+        if data_quota_bytes == 0 {
+            continue;
+        }
+        let (used_bytes, last_reset_epoch_secs) = snapshot
+            .get(&username)
+            .map(|entry| (entry.used_bytes, entry.last_reset_epoch_secs))
+            .unwrap_or((0, 0));
+        users.push(UserQuotaEntry {
+            username,
+            data_quota_bytes,
+            used_bytes,
+            last_reset_epoch_secs,
+        });
+    }
+    UserQuotaListData { users }
+}
+
+fn empty_user_links() -> UserLinks {
+    UserLinks {
+        classic: Vec::new(),
+        secure: Vec::new(),
+        tls: Vec::new(),
+        tls_domains: Vec::new(),
+    }
+}
+
 fn build_user_links(
    cfg: &ProxyConfig,
    secret: &str,
@@ -458,10 +618,12 @@ fn build_user_links(
        .public_port
        .unwrap_or(resolve_default_link_port(cfg));
    let tls_domains = resolve_tls_domains(cfg);
+    let extra_tls_domains = resolve_extra_tls_domains(cfg);

    let mut classic = Vec::new();
    let mut secure = Vec::new();
    let mut tls = Vec::new();
+    let mut tls_domain_links = Vec::new();

    for host in &hosts {
        if cfg.general.modes.classic {
@@ -484,6 +646,17 @@ fn build_user_links(
                    host, port, secret, domain_hex
                ));
            }
+            for domain in &extra_tls_domains {
+                let domain_hex = hex::encode(domain);
+                let link = format!(
+                    "tg://proxy?server={}&port={}&secret=ee{}{}",
+                    host, port, secret, domain_hex
+                );
+                tls_domain_links.push(TlsDomainLink {
+                    domain: (*domain).to_string(),
+                    link,
+                });
+            }
        }
    }

@@ -491,6 +664,7 @@ fn build_user_links(
        classic,
        secure,
        tls,
+        tls_domains: tls_domain_links,
    }
 }

@@ -607,6 +781,19 @@ fn resolve_tls_domains(cfg: &ProxyConfig) -> Vec<&str> {
    domains
 }

+fn resolve_extra_tls_domains(cfg: &ProxyConfig) -> Vec<&str> {
+    let mut domains = Vec::with_capacity(cfg.censorship.tls_domains.len());
+    let primary = cfg.censorship.tls_domain.as_str();
+    for domain in &cfg.censorship.tls_domains {
+        let value = domain.as_str();
+        if value.is_empty() || value == primary || domains.contains(&value) {
+            continue;
+        }
+        domains.push(value);
+    }
+    domains
+}
+
 #[cfg(test)]
 mod tests {
    use super::*;
@@ -661,6 +848,34 @@ mod tests {
        assert_eq!(alice.max_tcp_conns, None);
    }

+    #[tokio::test]
+    async fn users_from_config_reports_user_rate_limits() {
+        let mut cfg = ProxyConfig::default();
+        cfg.access.users.insert(
+            "alice".to_string(),
+            "0123456789abcdef0123456789abcdef".to_string(),
+        );
+        cfg.access.user_rate_limits.insert(
+            "alice".to_string(),
+            RateLimitBps {
+                up_bps: 1024,
+                down_bps: 0,
+            },
+        );
+
+        let stats = Stats::new();
+        let tracker = UserIpTracker::new();
+
+        let users = users_from_config(&cfg, &stats, &tracker, None, None, None).await;
+        let alice = users
+            .iter()
+            .find(|entry| entry.username == "alice")
+            .expect("alice must be present");
+
+        assert_eq!(alice.rate_limit_up_bps, Some(1024));
+        assert_eq!(alice.rate_limit_down_bps, None);
+    }
+
    #[tokio::test]
    async fn users_from_config_marks_runtime_membership_when_snapshot_is_provided() {
        let mut disk_cfg = ProxyConfig::default();
@@ -696,4 +911,144 @@ mod tests {
        assert!(alice.in_runtime);
        assert!(!bob.in_runtime);
    }
+
+    #[tokio::test]
+    async fn users_from_config_returns_tls_link_for_each_tls_domain() {
+        let mut cfg = ProxyConfig::default();
+        cfg.access.users.insert(
+            "alice".to_string(),
+            "0123456789abcdef0123456789abcdef".to_string(),
+        );
+        cfg.general.modes.classic = false;
+        cfg.general.modes.secure = false;
+        cfg.general.modes.tls = true;
+        cfg.general.links.public_host = Some("proxy.example.net".to_string());
+        cfg.general.links.public_port = Some(443);
+        cfg.censorship.tls_domain = "front-a.example.com".to_string();
+        cfg.censorship.tls_domains = vec![
+            "front-b.example.com".to_string(),
+            "front-c.example.com".to_string(),
+            "front-b.example.com".to_string(),
+            "front-a.example.com".to_string(),
+        ];
+
+        let stats = Stats::new();
+        let tracker = UserIpTracker::new();
+        let users = users_from_config(&cfg, &stats, &tracker, None, None, None).await;
+        let alice = users
+            .iter()
+            .find(|entry| entry.username == "alice")
+            .expect("alice must be present");
+
+        assert_eq!(alice.links.tls.len(), 3);
+        assert!(
+            alice
+                .links
+                .tls
+                .iter()
+                .any(|link| link.ends_with(&hex::encode("front-a.example.com")))
+        );
+        assert!(
+            alice
+                .links
+                .tls
+                .iter()
+                .any(|link| link.ends_with(&hex::encode("front-b.example.com")))
+        );
+        assert!(
+            alice
+                .links
+                .tls
+                .iter()
+                .any(|link| link.ends_with(&hex::encode("front-c.example.com")))
+        );
+        assert_eq!(alice.links.tls_domains.len(), 2);
+        assert!(
+            alice
+                .links
+                .tls_domains
+                .iter()
+                .any(|entry| entry.domain == "front-b.example.com"
+                    && entry.link.ends_with(&hex::encode("front-b.example.com")))
+        );
+        assert!(
+            alice
+                .links
+                .tls_domains
+                .iter()
+                .any(|entry| entry.domain == "front-c.example.com"
+                    && entry.link.ends_with(&hex::encode("front-c.example.com")))
+        );
+        assert!(
+            !alice
+                .links
+                .tls_domains
+                .iter()
+                .any(|entry| entry.domain == "front-a.example.com")
+        );
+    }
+
+    #[test]
+    fn build_user_quota_list_skips_users_without_positive_quota_and_sorts_by_username() {
+        let mut cfg = ProxyConfig::default();
+        cfg.access.users.insert(
+            "alice".to_string(),
+            "0123456789abcdef0123456789abcdef".to_string(),
+        );
+        cfg.access.users.insert(
+            "bob".to_string(),
+            "fedcba9876543210fedcba9876543210".to_string(),
+        );
+        cfg.access.users.insert(
+            "carol".to_string(),
+            "aaaabbbbccccddddeeeeffff00001111".to_string(),
+        );
+        // alice has a positive quota and should be listed.
+        cfg.access
+            .user_data_quota
+            .insert("alice".to_string(), 1 << 20);
+        // bob has no quota entry at all (None) — should be skipped.
+        // carol has an explicit zero quota — should be skipped.
+        cfg.access.user_data_quota.insert("carol".to_string(), 0);
+
+        let stats = Stats::new();
+        // Charge some traffic against alice; carol gets traffic too but should
+        // still be filtered out by the quota check.
+        let alice_stats = stats.get_or_create_user_stats_handle("alice");
+        stats.quota_charge_post_write(&alice_stats, 4096);
+        let carol_stats = stats.get_or_create_user_stats_handle("carol");
+        stats.quota_charge_post_write(&carol_stats, 99);
+
+        let data = build_user_quota_list(&cfg, &stats);
+
+        assert_eq!(data.users.len(), 1);
+        let entry = &data.users[0];
+        assert_eq!(entry.username, "alice");
+        assert_eq!(entry.data_quota_bytes, 1 << 20);
+        assert_eq!(entry.used_bytes, 4096);
+        assert_eq!(entry.last_reset_epoch_secs, 0);
+    }
+
+    #[test]
+    fn build_user_quota_list_orders_multiple_users_by_username_ascending() {
+        let mut cfg = ProxyConfig::default();
+        for name in ["charlie", "alice", "bob"] {
+            cfg.access.users.insert(
+                name.to_string(),
+                "0123456789abcdef0123456789abcdef".to_string(),
+            );
+            cfg.access.user_data_quota.insert(name.to_string(), 1 << 30);
+        }
+
+        let stats = Stats::new();
+        let data = build_user_quota_list(&cfg, &stats);
+
+        let names: Vec<&str> = data.users.iter().map(|e| e.username.as_str()).collect();
+        assert_eq!(names, vec!["alice", "bob", "charlie"]);
+        for entry in &data.users {
+            assert_eq!(entry.used_bytes, 0);
+            assert_eq!(entry.last_reset_epoch_secs, 0);
+            assert_eq!(entry.data_quota_bytes, 1 << 30);
+        }
+    }
 }
--- a/src/config/defaults.rs
+++ b/src/config/defaults.rs
@@ -102,7 +102,7 @@ pub(crate) fn default_fake_cert_len() -> usize {
 }

 pub(crate) fn default_tls_front_dir() -> String {
-    "/etc/telemt/tlsfront".to_string()
+    "tlsfront".to_string()
 }

 pub(crate) fn default_replay_check_len() -> usize {
@@ -568,7 +568,7 @@ pub(crate) fn default_beobachten_flush_secs() -> u64 {
 }

 pub(crate) fn default_beobachten_file() -> String {
-    "/etc/telemt/beobachten.txt".to_string()
+    "beobachten.txt".to_string()
 }

 pub(crate) fn default_tls_new_session_tickets() -> u8 {
--- a/src/config/load.rs
+++ b/src/config/load.rs
@@ -22,6 +22,672 @@ const MAX_ME_ROUTE_CHANNEL_CAPACITY: usize = 8_192;
 const MAX_ME_C2ME_CHANNEL_CAPACITY: usize = 8_192;
 const MIN_MAX_CLIENT_FRAME_BYTES: usize = 4 * 1024;
 const MAX_MAX_CLIENT_FRAME_BYTES: usize = 16 * 1024 * 1024;
+const MAX_API_REQUEST_BODY_LIMIT_BYTES: usize = 1024 * 1024;
+
+fn is_valid_tls_domain_name(domain: &str) -> bool {
+    !domain.is_empty()
+        && !domain
+            .chars()
+            .any(|ch| ch.is_whitespace() || matches!(ch, '/' | '\\'))
+}
+
+const TOP_LEVEL_CONFIG_KEYS: &[&str] = &[
+    "general",
+    "network",
+    "server",
+    "timeouts",
+    "censorship",
+    "access",
+    "upstreams",
+    "show_link",
+    "dc_overrides",
+    "default_dc",
+    "beobachten",
+    "beobachten_minutes",
+    "beobachten_flush_secs",
+    "beobachten_file",
+    "include",
+];
+
+const GENERAL_CONFIG_KEYS: &[&str] = &[
+    "data_path",
+    "quota_state_path",
+    "config_strict",
+    "modes",
+    "prefer_ipv6",
+    "fast_mode",
+    "use_middle_proxy",
+    "proxy_secret_path",
+    "proxy_secret_url",
+    "proxy_config_v4_cache_path",
+    "proxy_config_v4_url",
+    "proxy_config_v6_cache_path",
+    "proxy_config_v6_url",
+    "ad_tag",
+    "middle_proxy_nat_ip",
+    "middle_proxy_nat_probe",
+    "middle_proxy_nat_stun",
+    "middle_proxy_nat_stun_servers",
+    "stun_nat_probe_concurrency",
+    "middle_proxy_pool_size",
+    "middle_proxy_warm_standby",
+    "me_init_retry_attempts",
+    "me2dc_fallback",
+    "me2dc_fast",
+    "me_keepalive_enabled",
+    "me_keepalive_interval_secs",
+    "me_keepalive_jitter_secs",
+    "me_keepalive_payload_random",
+    "rpc_proxy_req_every",
+    "me_writer_cmd_channel_capacity",
+    "me_route_channel_capacity",
+    "me_c2me_channel_capacity",
+    "me_c2me_send_timeout_ms",
+    "me_reader_route_data_wait_ms",
+    "me_d2c_flush_batch_max_frames",
+    "me_d2c_flush_batch_max_bytes",
+    "me_d2c_flush_batch_max_delay_us",
+    "me_d2c_ack_flush_immediate",
+    "me_quota_soft_overshoot_bytes",
+    "me_d2c_frame_buf_shrink_threshold_bytes",
+    "direct_relay_copy_buf_c2s_bytes",
+    "direct_relay_copy_buf_s2c_bytes",
+    "crypto_pending_buffer",
+    "max_client_frame",
+    "desync_all_full",
+    "beobachten",
+    "beobachten_minutes",
+    "beobachten_flush_secs",
+    "beobachten_file",
+    "hardswap",
+    "me_warmup_stagger_enabled",
+    "me_warmup_step_delay_ms",
+    "me_warmup_step_jitter_ms",
+    "me_reconnect_max_concurrent_per_dc",
+    "me_reconnect_backoff_base_ms",
+    "me_reconnect_backoff_cap_ms",
+    "me_reconnect_fast_retry_count",
+    "me_single_endpoint_shadow_writers",
+    "me_single_endpoint_outage_mode_enabled",
+    "me_single_endpoint_outage_disable_quarantine",
+    "me_single_endpoint_outage_backoff_min_ms",
+    "me_single_endpoint_outage_backoff_max_ms",
+    "me_single_endpoint_shadow_rotate_every_secs",
+    "me_floor_mode",
+    "me_adaptive_floor_idle_secs",
+    "me_adaptive_floor_min_writers_single_endpoint",
+    "me_adaptive_floor_min_writers_multi_endpoint",
+    "me_adaptive_floor_recover_grace_secs",
+    "me_adaptive_floor_writers_per_core_total",
+    "me_adaptive_floor_cpu_cores_override",
+    "me_adaptive_floor_max_extra_writers_single_per_core",
+    "me_adaptive_floor_max_extra_writers_multi_per_core",
+    "me_adaptive_floor_max_active_writers_per_core",
+    "me_adaptive_floor_max_warm_writers_per_core",
+    "me_adaptive_floor_max_active_writers_global",
+    "me_adaptive_floor_max_warm_writers_global",
+    "upstream_connect_retry_attempts",
+    "upstream_connect_retry_backoff_ms",
+    "upstream_connect_budget_ms",
+    "tg_connect",
+    "upstream_unhealthy_fail_threshold",
+    "upstream_connect_failfast_hard_errors",
+    "stun_iface_mismatch_ignore",
+    "unknown_dc_log_path",
+    "unknown_dc_file_log_enabled",
+    "log_level",
+    "disable_colors",
+    "telemetry",
+    "me_socks_kdf_policy",
+    "me_route_backpressure_enabled",
+    "me_route_fairshare_enabled",
+    "me_route_backpressure_base_timeout_ms",
+    "me_route_backpressure_high_timeout_ms",
+    "me_route_backpressure_high_watermark_pct",
+    "me_health_interval_ms_unhealthy",
+    "me_health_interval_ms_healthy",
+    "me_admission_poll_ms",
+    "me_warn_rate_limit_ms",
+    "me_route_no_writer_mode",
+    "me_route_no_writer_wait_ms",
+    "me_route_hybrid_max_wait_ms",
+    "me_route_blocking_send_timeout_ms",
+    "me_route_inline_recovery_attempts",
+    "me_route_inline_recovery_wait_ms",
+    "links",
+    "fast_mode_min_tls_record",
+    "update_every",
+    "me_reinit_every_secs",
+    "me_hardswap_warmup_delay_min_ms",
+    "me_hardswap_warmup_delay_max_ms",
+    "me_hardswap_warmup_extra_passes",
+    "me_hardswap_warmup_pass_backoff_base_ms",
+    "me_config_stable_snapshots",
+    "me_config_apply_cooldown_secs",
+    "me_snapshot_require_http_2xx",
+    "me_snapshot_reject_empty_map",
+    "me_snapshot_min_proxy_for_lines",
+    "proxy_secret_stable_snapshots",
+    "proxy_secret_rotate_runtime",
+    "me_secret_atomic_snapshot",
+    "proxy_secret_len_max",
+    "me_pool_drain_ttl_secs",
+    "me_instadrain",
+    "me_pool_drain_threshold",
+    "me_pool_drain_soft_evict_enabled",
+    "me_pool_drain_soft_evict_grace_secs",
+    "me_pool_drain_soft_evict_per_writer",
+    "me_pool_drain_soft_evict_budget_per_core",
+    "me_pool_drain_soft_evict_cooldown_ms",
+    "me_bind_stale_mode",
+    "me_bind_stale_ttl_secs",
+    "me_pool_min_fresh_ratio",
+    "me_reinit_drain_timeout_secs",
+    "proxy_secret_auto_reload_secs",
+    "proxy_config_auto_reload_secs",
+    "me_reinit_singleflight",
+    "me_reinit_trigger_channel",
+    "me_reinit_coalesce_window_ms",
+    "me_deterministic_writer_sort",
+    "me_writer_pick_mode",
+    "me_writer_pick_sample_size",
+    "ntp_check",
+    "ntp_servers",
+    "auto_degradation_enabled",
+    "degradation_min_unavailable_dc_groups",
+    "rst_on_close",
+];
+
+const NETWORK_CONFIG_KEYS: &[&str] = &[
+    "ipv4",
+    "ipv6",
+    "prefer",
+    "multipath",
+    "stun_use",
+    "stun_servers",
+    "stun_tcp_fallback",
+    "http_ip_detect_urls",
+    "cache_public_ip_path",
+    "dns_overrides",
+];
+
+const SERVER_CONFIG_KEYS: &[&str] = &[
+    "port",
+    "listen_addr_ipv4",
+    "listen_addr_ipv6",
+    "listen_unix_sock",
+    "listen_unix_sock_perm",
+    "listen_tcp",
+    "proxy_protocol",
+    "proxy_protocol_header_timeout_ms",
+    "proxy_protocol_trusted_cidrs",
+    "metrics_port",
+    "metrics_listen",
+    "metrics_whitelist",
+    "api",
+    "admin_api",
+    "listeners",
+    "listen_backlog",
+    "max_connections",
+    "accept_permit_timeout_ms",
+    "conntrack_control",
+];
+
+const API_CONFIG_KEYS: &[&str] = &[
+    "enabled",
+    "listen",
+    "whitelist",
+    "gray_action",
+    "auth_header",
+    "request_body_limit_bytes",
+    "minimal_runtime_enabled",
+    "minimal_runtime_cache_ttl_ms",
+    "runtime_edge_enabled",
+    "runtime_edge_cache_ttl_ms",
+    "runtime_edge_top_n",
+    "runtime_edge_events_capacity",
+    "read_only",
+];
+
+const CONNTRACK_CONTROL_CONFIG_KEYS: &[&str] = &[
+    "inline_conntrack_control",
+    "mode",
+    "backend",
+    "profile",
+    "hybrid_listener_ips",
+    "pressure_high_watermark_pct",
+    "pressure_low_watermark_pct",
+    "delete_budget_per_sec",
+];
+
+const LISTENER_CONFIG_KEYS: &[&str] = &[
+    "ip",
+    "port",
+    "announce",
+    "announce_ip",
+    "proxy_protocol",
+    "reuse_allow",
+];
+
+const TIMEOUTS_CONFIG_KEYS: &[&str] = &[
+    "client_first_byte_idle_secs",
+    "client_handshake",
+    "relay_idle_policy_v2_enabled",
+    "relay_client_idle_soft_secs",
+    "relay_client_idle_hard_secs",
+    "relay_idle_grace_after_downstream_activity_secs",
+    "client_keepalive",
+    "client_ack",
+    "me_one_retry",
+    "me_one_timeout_ms",
+];
+
+const CENSORSHIP_CONFIG_KEYS: &[&str] = &[
+    "tls_domain",
+    "tls_domains",
+    "unknown_sni_action",
+    "tls_fetch_scope",
+    "tls_fetch",
+    "mask",
+    "mask_host",
+    "mask_port",
+    "mask_unix_sock",
+    "fake_cert_len",
+    "tls_emulation",
+    "tls_front_dir",
+    "server_hello_delay_min_ms",
+    "server_hello_delay_max_ms",
+    "tls_new_session_tickets",
+    "serverhello_compact",
+    "tls_full_cert_ttl_secs",
+    "alpn_enforce",
+    "mask_proxy_protocol",
+    "mask_shape_hardening",
+    "mask_shape_hardening_aggressive_mode",
+    "mask_shape_bucket_floor_bytes",
+    "mask_shape_bucket_cap_bytes",
+    "mask_shape_above_cap_blur",
+    "mask_shape_above_cap_blur_max_bytes",
+    "mask_relay_max_bytes",
+    "mask_relay_timeout_ms",
+    "mask_relay_idle_timeout_ms",
+    "mask_classifier_prefetch_timeout_ms",
+    "mask_timing_normalization_enabled",
+    "mask_timing_normalization_floor_ms",
+    "mask_timing_normalization_ceiling_ms",
+];
+
+const TLS_FETCH_CONFIG_KEYS: &[&str] = &[
+    "profiles",
+    "strict_route",
+    "attempt_timeout_ms",
+    "total_budget_ms",
+    "grease_enabled",
+    "deterministic",
+    "profile_cache_ttl_secs",
+];
+
+const ACCESS_CONFIG_KEYS: &[&str] = &[
+    "users",
+    "user_ad_tags",
+    "user_max_tcp_conns",
+    "user_max_tcp_conns_global_each",
+    "user_expirations",
+    "user_data_quota",
+    "user_rate_limits",
+    "cidr_rate_limits",
+    "user_max_unique_ips",
+    "user_max_unique_ips_global_each",
+    "user_max_unique_ips_mode",
+    "user_max_unique_ips_window_secs",
+    "replay_check_len",
+    "replay_window_secs",
+    "ignore_time_skew",
+];
+
+const RATE_LIMIT_BPS_CONFIG_KEYS: &[&str] = &["up_bps", "down_bps"];
+
+const UPSTREAM_CONFIG_KEYS: &[&str] = &[
+    "type",
+    "interface",
+    "bind_addresses",
+    "bindtodevice",
+    "force_bind",
+    "address",
+    "user_id",
+    "username",
+    "password",
+    "url",
+    "weight",
+    "enabled",
+    "scopes",
+    "ipv4",
+    "ipv6",
+];
+
+const PROXY_MODES_CONFIG_KEYS: &[&str] = &["classic", "secure", "tls"];
+const TELEMETRY_CONFIG_KEYS: &[&str] = &["core_enabled", "user_enabled", "me_level"];
+const LINKS_CONFIG_KEYS: &[&str] = &["show", "public_host", "public_port"];
+
+#[derive(Debug)]
+struct UnknownConfigKey {
+    path: String,
+    suggestion: Option<String>,
+}
+
+fn table_at<'a>(value: &'a toml::Value, path: &[&str]) -> Option<&'a toml::Table> {
+    let mut current = value;
+    for segment in path {
+        current = current.get(*segment)?;
+    }
+    current.as_table()
+}
+
+fn is_strict_config(parsed_toml: &toml::Value) -> bool {
+    table_at(parsed_toml, &["general"])
+        .and_then(|table| table.get("config_strict"))
+        .and_then(toml::Value::as_bool)
+        .unwrap_or(false)
+}
+
+fn known_config_keys_for_suggestion() -> Vec<&'static str> {
+    let mut keys = Vec::new();
+    for group in [
+        TOP_LEVEL_CONFIG_KEYS,
+        GENERAL_CONFIG_KEYS,
+        NETWORK_CONFIG_KEYS,
+        SERVER_CONFIG_KEYS,
+        API_CONFIG_KEYS,
+        CONNTRACK_CONTROL_CONFIG_KEYS,
+        LISTENER_CONFIG_KEYS,
+        TIMEOUTS_CONFIG_KEYS,
+        CENSORSHIP_CONFIG_KEYS,
+        TLS_FETCH_CONFIG_KEYS,
+        ACCESS_CONFIG_KEYS,
+        RATE_LIMIT_BPS_CONFIG_KEYS,
+        UPSTREAM_CONFIG_KEYS,
+        PROXY_MODES_CONFIG_KEYS,
+        TELEMETRY_CONFIG_KEYS,
+        LINKS_CONFIG_KEYS,
+    ] {
+        keys.extend_from_slice(group);
+    }
+    keys
+}
+
+fn levenshtein_distance(a: &str, b: &str) -> usize {
+    let b_chars: Vec<char> = b.chars().collect();
+    let mut prev: Vec<usize> = (0..=b_chars.len()).collect();
+    let mut curr = vec![0usize; b_chars.len() + 1];
+
+    for (i, ca) in a.chars().enumerate() {
+        curr[0] = i + 1;
+        for (j, cb) in b_chars.iter().enumerate() {
+            let replace = if ca == *cb { prev[j] } else { prev[j] + 1 };
+            curr[j + 1] = (prev[j + 1] + 1).min(curr[j] + 1).min(replace);
+        }
+        std::mem::swap(&mut prev, &mut curr);
+    }
+
+    prev[b_chars.len()]
+}
+
+fn unknown_key_suggestion(key: &str, known_keys: &[&'static str]) -> Option<String> {
+    let normalized = key.to_ascii_lowercase();
+    let mut best: Option<(&str, usize)> = None;
+    for known in known_keys {
+        let distance = levenshtein_distance(&normalized, known);
+        let is_better = match best {
+            Some((_, best_distance)) => distance < best_distance,
+            None => true,
+        };
+        if distance <= 4 && is_better {
+            best = Some((known, distance));
+        }
+    }
+    best.map(|(known, _)| known.to_string())
+}
+
+fn push_unknown_keys(
+    unknown: &mut Vec<UnknownConfigKey>,
+    known_for_suggestion: &[&'static str],
+    path: &str,
+    table: &toml::Table,
+    allowed: &[&str],
+) {
+    for key in table.keys() {
+        if !allowed.contains(&key.as_str()) {
+            let full_path = if path.is_empty() {
+                key.clone()
+            } else {
+                format!("{path}.{key}")
+            };
+            unknown.push(UnknownConfigKey {
+                path: full_path,
+                suggestion: unknown_key_suggestion(key, known_for_suggestion),
+            });
+        }
+    }
+}
+
+fn check_known_table(
+    parsed_toml: &toml::Value,
+    unknown: &mut Vec<UnknownConfigKey>,
+    known_for_suggestion: &[&'static str],
+    path: &[&str],
+    allowed: &[&str],
+) {
+    if let Some(table) = table_at(parsed_toml, path) {
+        push_unknown_keys(
+            unknown,
+            known_for_suggestion,
+            &path.join("."),
+            table,
+            allowed,
+        );
+    }
+}
+
+fn check_nested_table_value(
+    unknown: &mut Vec<UnknownConfigKey>,
+    known_for_suggestion: &[&'static str],
+    path: String,
+    value: &toml::Value,
+    allowed: &[&str],
+) {
+    if let Some(table) = value.as_table() {
+        push_unknown_keys(unknown, known_for_suggestion, &path, table, allowed);
+    }
+}
+
+fn collect_unknown_config_keys(parsed_toml: &toml::Value) -> Vec<UnknownConfigKey> {
+    let known_for_suggestion = known_config_keys_for_suggestion();
+    let mut unknown = Vec::new();
+
+    if let Some(root) = parsed_toml.as_table() {
+        push_unknown_keys(
+            &mut unknown,
+            &known_for_suggestion,
+            "",
+            root,
+            TOP_LEVEL_CONFIG_KEYS,
+        );
+    }
+
+    check_known_table(
+        parsed_toml,
+        &mut unknown,
+        &known_for_suggestion,
+        &["general"],
+        GENERAL_CONFIG_KEYS,
+    );
+    check_known_table(
+        parsed_toml,
+        &mut unknown,
+        &known_for_suggestion,
+        &["general", "modes"],
+        PROXY_MODES_CONFIG_KEYS,
+    );
+    check_known_table(
+        parsed_toml,
+        &mut unknown,
+        &known_for_suggestion,
+        &["general", "telemetry"],
+        TELEMETRY_CONFIG_KEYS,
+    );
+    check_known_table(
+        parsed_toml,
+        &mut unknown,
+        &known_for_suggestion,
+        &["general", "links"],
+        LINKS_CONFIG_KEYS,
+    );
+    check_known_table(
+        parsed_toml,
+        &mut unknown,
+        &known_for_suggestion,
+        &["network"],
+        NETWORK_CONFIG_KEYS,
+    );
+    check_known_table(
+        parsed_toml,
+        &mut unknown,
+        &known_for_suggestion,
+        &["server"],
+        SERVER_CONFIG_KEYS,
+    );
+    check_known_table(
+        parsed_toml,
+        &mut unknown,
+        &known_for_suggestion,
+        &["server", "api"],
+        API_CONFIG_KEYS,
+    );
+    check_known_table(
+        parsed_toml,
+        &mut unknown,
+        &known_for_suggestion,
+        &["server", "admin_api"],
+        API_CONFIG_KEYS,
+    );
+    check_known_table(
+        parsed_toml,
+        &mut unknown,
+        &known_for_suggestion,
+        &["server", "conntrack_control"],
+        CONNTRACK_CONTROL_CONFIG_KEYS,
+    );
+    check_known_table(
+        parsed_toml,
+        &mut unknown,
+        &known_for_suggestion,
+        &["timeouts"],
+        TIMEOUTS_CONFIG_KEYS,
+    );
+    check_known_table(
+        parsed_toml,
+        &mut unknown,
+        &known_for_suggestion,
+        &["censorship"],
+        CENSORSHIP_CONFIG_KEYS,
+    );
+    check_known_table(
+        parsed_toml,
+        &mut unknown,
+        &known_for_suggestion,
+        &["censorship", "tls_fetch"],
+        TLS_FETCH_CONFIG_KEYS,
+    );
+    check_known_table(
+        parsed_toml,
+        &mut unknown,
+        &known_for_suggestion,
+        &["access"],
+        ACCESS_CONFIG_KEYS,
+    );
+
+    if let Some(listeners) = table_at(parsed_toml, &["server"])
+        .and_then(|table| table.get("listeners"))
+        .and_then(toml::Value::as_array)
+    {
+        for (idx, listener) in listeners.iter().enumerate() {
+            check_nested_table_value(
+                &mut unknown,
+                &known_for_suggestion,
+                format!("server.listeners[{idx}]"),
+                listener,
+                LISTENER_CONFIG_KEYS,
+            );
+        }
+    }
+
+    if let Some(upstreams) = parsed_toml.get("upstreams").and_then(toml::Value::as_array) {
+        for (idx, upstream) in upstreams.iter().enumerate() {
+            check_nested_table_value(
+                &mut unknown,
+                &known_for_suggestion,
+                format!("upstreams[{idx}]"),
+                upstream,
+                UPSTREAM_CONFIG_KEYS,
+            );
+        }
+    }
+
+    for access_map in ["user_rate_limits", "cidr_rate_limits"] {
+        if let Some(table) = table_at(parsed_toml, &["access"])
+            .and_then(|access| access.get(access_map))
+            .and_then(toml::Value::as_table)
+        {
+            for (entry_name, value) in table {
+                check_nested_table_value(
+                    &mut unknown,
+                    &known_for_suggestion,
+                    format!("access.{access_map}.{entry_name}"),
+                    value,
+                    RATE_LIMIT_BPS_CONFIG_KEYS,
+                );
+            }
+        }
+    }
+
+    unknown
+}
+
+fn handle_unknown_config_keys(parsed_toml: &toml::Value) -> Result<()> {
+    let unknown = collect_unknown_config_keys(parsed_toml);
+    if unknown.is_empty() {
+        return Ok(());
+    }
+
+    for item in &unknown {
+        if let Some(suggestion) = item.suggestion.as_deref() {
+            warn!(
+                key = %item.path,
+                suggestion = %suggestion,
+                "Unknown config key ignored; did you mean the suggested key?"
+            );
+        } else {
+            warn!(key = %item.path, "Unknown config key ignored");
+        }
+    }
+
+    if is_strict_config(parsed_toml) {
+        let mut paths = Vec::with_capacity(unknown.len());
+        for item in unknown {
+            if let Some(suggestion) = item.suggestion {
+                paths.push(format!("{} (did you mean `{}`?)", item.path, suggestion));
+            } else {
+                paths.push(item.path);
+            }
+        }
+        return Err(ProxyError::Config(format!(
+            "unknown config keys are not allowed when general.config_strict=true: {}",
+            paths.join(", ")
+        )));
+    }
+
+    Ok(())
+}

 #[derive(Debug, Clone)]
 pub(crate) struct LoadedConfig {
@@ -337,6 +1003,7 @@ impl ProxyConfig {

        let parsed_toml: toml::Value =
            toml::from_str(&processed).map_err(|e| ProxyError::Config(e.to_string()))?;
+        handle_unknown_config_keys(&parsed_toml)?;
        let general_table = parsed_toml
            .get("general")
            .and_then(|value| value.as_table());
@@ -1087,9 +1754,9 @@ impl ProxyConfig {
            ));
        }

-        if config.general.me_route_blocking_send_timeout_ms > 5000 {
+        if !(1..=5000).contains(&config.general.me_route_blocking_send_timeout_ms) {
            return Err(ProxyError::Config(
-                "general.me_route_blocking_send_timeout_ms must be within [0, 5000]".to_string(),
+                "general.me_route_blocking_send_timeout_ms must be within [1, 5000]".to_string(),
            ));
        }

@@ -1111,9 +1778,11 @@ impl ProxyConfig {
            ));
        }

-        if config.server.api.request_body_limit_bytes == 0 {
+        if !(1..=MAX_API_REQUEST_BODY_LIMIT_BYTES)
+            .contains(&config.server.api.request_body_limit_bytes)
+        {
            return Err(ProxyError::Config(
-                "server.api.request_body_limit_bytes must be > 0".to_string(),
+                "server.api.request_body_limit_bytes must be within [1, 1048576]".to_string(),
            ));
        }

@@ -1441,13 +2110,22 @@ impl ProxyConfig {
            return Err(ProxyError::Config("No modes enabled".to_string()));
        }

-        if self.censorship.tls_domain.contains(' ') || self.censorship.tls_domain.contains('/') {
+        if !is_valid_tls_domain_name(&self.censorship.tls_domain) {
            return Err(ProxyError::Config(format!(
                "Invalid tls_domain: '{}'. Must be a valid domain name",
                self.censorship.tls_domain
            )));
        }

+        for domain in &self.censorship.tls_domains {
+            if !is_valid_tls_domain_name(domain) {
+                return Err(ProxyError::Config(format!(
+                    "Invalid tls_domains entry: '{}'. Must be a valid domain name",
+                    domain
+                )));
+            }
+        }
+
        for (user, tag) in &self.access.user_ad_tags {
            let zeros = "00000000000000000000000000000000";
            if !is_valid_ad_tag(tag) {
@@ -2602,6 +3280,26 @@ mod tests {
        let _ = std::fs::remove_file(path);
    }

+    #[test]
+    fn me_route_blocking_send_timeout_ms_zero_is_rejected() {
+        let toml = r#"
+            [general]
+            me_route_blocking_send_timeout_ms = 0
+
+            [censorship]
+            tls_domain = "example.com"
+
+            [access.users]
+            user = "00000000000000000000000000000000"
+        "#;
+        let dir = std::env::temp_dir();
+        let path = dir.join("telemt_me_route_blocking_send_timeout_zero_test.toml");
+        std::fs::write(&path, toml).unwrap();
+        let err = ProxyConfig::load(&path).unwrap_err().to_string();
+        assert!(err.contains("general.me_route_blocking_send_timeout_ms must be within [1, 5000]"));
+        let _ = std::fs::remove_file(path);
+    }
+
    #[test]
    fn me_route_no_writer_mode_is_parsed() {
        let toml = r#"
--- a/src/config/types.rs
+++ b/src/config/types.rs
@@ -26,6 +26,10 @@ pub enum LogLevel {
    Silent,
 }

+fn default_quota_state_path() -> PathBuf {
+    PathBuf::from("telemt.limit.json")
+}
+
 impl LogLevel {
    /// Convert to tracing EnvFilter directive string.
    pub fn to_filter_str(&self) -> &'static str {
@@ -375,6 +379,15 @@ pub struct GeneralConfig {
    #[serde(default)]
    pub data_path: Option<PathBuf>,

+    /// JSON state file for runtime per-user quota consumption.
+    #[serde(default = "default_quota_state_path")]
+    pub quota_state_path: PathBuf,
+
+    /// Reject unknown TOML config keys during load.
+    /// Startup fails fast; hot-reload rejects the new snapshot and keeps the current config.
+    #[serde(default)]
+    pub config_strict: bool,
+
    #[serde(default)]
    pub modes: ProxyModes,

@@ -530,10 +543,17 @@ pub struct GeneralConfig {
    pub me_d2c_frame_buf_shrink_threshold_bytes: usize,

    /// Copy buffer size for client->DC direction in direct relay.
+    ///
+    /// This is also the upper bound for one amortized upload rate-limit burst:
+    /// upload debt is settled before the next relay read instead of blocking
+    /// inside the completed read path.
    #[serde(default = "default_direct_relay_copy_buf_c2s_bytes")]
    pub direct_relay_copy_buf_c2s_bytes: usize,

    /// Copy buffer size for DC->client direction in direct relay.
+    ///
+    /// This bounds one direct download rate-limit grant because writes are
+    /// clipped to the currently available shaper budget.
    #[serde(default = "default_direct_relay_copy_buf_s2c_bytes")]
    pub direct_relay_copy_buf_s2c_bytes: usize,

@@ -778,7 +798,7 @@ pub struct GeneralConfig {
    pub me_route_hybrid_max_wait_ms: u64,

    /// Maximum wait in milliseconds for blocking ME writer channel send fallback.
-    /// `0` keeps legacy unbounded wait behavior.
+    /// Must be within [1, 5000].
    #[serde(default = "default_me_route_blocking_send_timeout_ms")]
    pub me_route_blocking_send_timeout_ms: u64,

@@ -974,6 +994,8 @@ impl Default for GeneralConfig {
    fn default() -> Self {
        Self {
            data_path: None,
+            quota_state_path: default_quota_state_path(),
+            config_strict: false,
            modes: ProxyModes::default(),
            prefer_ipv6: false,
            fast_mode: default_true(),
@@ -1876,17 +1898,26 @@ pub struct AccessConfig {
    ///
    /// Each entry supports independent upload (`up_bps`) and download
    /// (`down_bps`) ceilings. A value of `0` in one direction means
-    /// "unlimited" for that direction.
+    /// "unlimited" for that direction. Limits are amortized: a relay quantum
+    /// may pass as a bounded burst, and the limiter applies the resulting wait
+    /// before later traffic in the same direction proceeds.
    #[serde(default)]
    pub user_rate_limits: HashMap<String, RateLimitBps>,

    /// Per-CIDR aggregate transport rate limits in bits-per-second.
    ///
    /// Matching uses longest-prefix-wins semantics. A value of `0` in one
-    /// direction means "unlimited" for that direction.
+    /// direction means "unlimited" for that direction. Limits are amortized
+    /// with the same bounded-burst contract as per-user rate limits.
    #[serde(default)]
    pub cidr_rate_limits: HashMap<IpNetwork, RateLimitBps>,

+    /// Per-username client source IP/CIDR deny list. Checked after successful
+    /// authentication; matching IPs get the same rejection path as invalid auth
+    /// (handshake fails closed for that connection).
+    #[serde(default)]
+    pub user_source_deny: HashMap<String, Vec<IpNetwork>>,
+
    #[serde(default)]
    pub user_max_unique_ips: HashMap<String, usize>,

@@ -1922,6 +1953,7 @@ impl Default for AccessConfig {
            user_data_quota: HashMap::new(),
            user_rate_limits: HashMap::new(),
            cidr_rate_limits: HashMap::new(),
+            user_source_deny: HashMap::new(),
            user_max_unique_ips: HashMap::new(),
            user_max_unique_ips_global_each: default_user_max_unique_ips_global_each(),
            user_max_unique_ips_mode: UserMaxUniqueIpsMode::default(),
@@ -1933,6 +1965,15 @@ impl Default for AccessConfig {
    }
 }

+impl AccessConfig {
+    /// Returns true if `ip` is contained in any CIDR listed for `username` under `user_source_deny`.
+    pub fn is_user_source_ip_denied(&self, username: &str, ip: IpAddr) -> bool {
+        self.user_source_deny
+            .get(username)
+            .is_some_and(|nets| nets.iter().any(|n| n.contains(ip)))
+    }
+}
+
 #[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Serialize, Deserialize)]
 pub struct RateLimitBps {
    #[serde(default)]
--- a/src/error.rs
+++ b/src/error.rs
@@ -222,6 +222,21 @@ pub enum ProxyError {
    #[error("Proxy error: {0}")]
    Proxy(String),

+    #[error("ME connection lost")]
+    MiddleConnectionLost,
+
+    #[error("Session terminated")]
+    RouteSwitched,
+
+    #[error("Traffic budget wait cancelled")]
+    TrafficBudgetWaitCancelled,
+
+    #[error("Traffic budget wait deadline exceeded")]
+    TrafficBudgetWaitDeadlineExceeded,
+
+    #[error("ME client writer cancelled")]
+    MiddleClientWriterCancelled,
+
    // ============= Config Errors =============
    #[error("Config error: {0}")]
    Config(String),
--- a/src/ip_tracker.rs
+++ b/src/ip_tracker.rs
@@ -9,30 +9,53 @@ use std::sync::Mutex;
 use std::sync::atomic::{AtomicU64, Ordering};
 use std::time::{Duration, Instant};

-use tokio::sync::{Mutex as AsyncMutex, RwLock};
+use tokio::sync::{Mutex as AsyncMutex, RwLock, RwLockWriteGuard};

 use crate::config::UserMaxUniqueIpsMode;

+const CLEANUP_DRAIN_BATCH_LIMIT: usize = 1024;
+const MAX_ACTIVE_IP_ENTRIES: u64 = 131_072;
+const MAX_RECENT_IP_ENTRIES: u64 = 262_144;
+
+/// Tracks active and recent client IPs for per-user admission control.
 #[derive(Debug, Clone)]
 pub struct UserIpTracker {
    active_ips: Arc<RwLock<HashMap<String, HashMap<IpAddr, usize>>>>,
    recent_ips: Arc<RwLock<HashMap<String, HashMap<IpAddr, Instant>>>>,
+    active_entry_count: Arc<AtomicU64>,
+    recent_entry_count: Arc<AtomicU64>,
+    active_cap_rejects: Arc<AtomicU64>,
+    recent_cap_rejects: Arc<AtomicU64>,
+    cleanup_deferred_releases: Arc<AtomicU64>,
    max_ips: Arc<RwLock<HashMap<String, usize>>>,
    default_max_ips: Arc<RwLock<usize>>,
    limit_mode: Arc<RwLock<UserMaxUniqueIpsMode>>,
    limit_window: Arc<RwLock<Duration>>,
    last_compact_epoch_secs: Arc<AtomicU64>,
-    cleanup_queue: Arc<Mutex<Vec<(String, IpAddr)>>>,
+    cleanup_queue_len: Arc<AtomicU64>,
+    cleanup_queue: Arc<Mutex<HashMap<(String, IpAddr), usize>>>,
    cleanup_drain_lock: Arc<AsyncMutex<()>>,
 }

+/// Point-in-time memory counters for user/IP limiter state.
 #[derive(Debug, Clone, Copy)]
 pub struct UserIpTrackerMemoryStats {
+    /// Number of users with active IP state.
    pub active_users: usize,
+    /// Number of users with recent IP state.
    pub recent_users: usize,
+    /// Number of active `(user, ip)` entries.
    pub active_entries: usize,
+    /// Number of recent-window `(user, ip)` entries.
    pub recent_entries: usize,
+    /// Number of deferred disconnect cleanups waiting to be drained.
    pub cleanup_queue_len: usize,
+    /// Number of new connections rejected by the global active-entry cap.
+    pub active_cap_rejects: u64,
+    /// Number of new connections rejected by the global recent-entry cap.
+    pub recent_cap_rejects: u64,
+    /// Number of release cleanups deferred through the cleanup queue.
+    pub cleanup_deferred_releases: u64,
 }

 impl UserIpTracker {
@@ -40,22 +63,81 @@ impl UserIpTracker {
        Self {
            active_ips: Arc::new(RwLock::new(HashMap::new())),
            recent_ips: Arc::new(RwLock::new(HashMap::new())),
+            active_entry_count: Arc::new(AtomicU64::new(0)),
+            recent_entry_count: Arc::new(AtomicU64::new(0)),
+            active_cap_rejects: Arc::new(AtomicU64::new(0)),
+            recent_cap_rejects: Arc::new(AtomicU64::new(0)),
+            cleanup_deferred_releases: Arc::new(AtomicU64::new(0)),
            max_ips: Arc::new(RwLock::new(HashMap::new())),
            default_max_ips: Arc::new(RwLock::new(0)),
            limit_mode: Arc::new(RwLock::new(UserMaxUniqueIpsMode::ActiveWindow)),
            limit_window: Arc::new(RwLock::new(Duration::from_secs(30))),
            last_compact_epoch_secs: Arc::new(AtomicU64::new(0)),
-            cleanup_queue: Arc::new(Mutex::new(Vec::new())),
+            cleanup_queue_len: Arc::new(AtomicU64::new(0)),
+            cleanup_queue: Arc::new(Mutex::new(HashMap::new())),
            cleanup_drain_lock: Arc::new(AsyncMutex::new(())),
        }
    }

+    fn decrement_counter(counter: &AtomicU64, amount: usize) {
+        if amount == 0 {
+            return;
+        }
+        let amount = amount as u64;
+        let _ = counter.fetch_update(Ordering::AcqRel, Ordering::Relaxed, |current| {
+            Some(current.saturating_sub(amount))
+        });
+    }
+
+    fn apply_active_cleanup(
+        active_ips: &mut HashMap<String, HashMap<IpAddr, usize>>,
+        user: &str,
+        ip: IpAddr,
+        pending_count: usize,
+    ) -> usize {
+        if pending_count == 0 {
+            return 0;
+        }
+
+        let mut remove_user = false;
+        let mut removed_active_entries = 0usize;
+        if let Some(user_ips) = active_ips.get_mut(user) {
+            if let Some(count) = user_ips.get_mut(&ip) {
+                if *count > pending_count {
+                    *count -= pending_count;
+                } else if user_ips.remove(&ip).is_some() {
+                    removed_active_entries = 1;
+                }
+            }
+            remove_user = user_ips.is_empty();
+        }
+        if remove_user {
+            active_ips.remove(user);
+        }
+        removed_active_entries
+    }
+
+    /// Queues a deferred active IP cleanup for a later async drain.
    pub fn enqueue_cleanup(&self, user: String, ip: IpAddr) {
        match self.cleanup_queue.lock() {
-            Ok(mut queue) => queue.push((user, ip)),
+            Ok(mut queue) => {
+                let count = queue.entry((user, ip)).or_insert(0);
+                if *count == 0 {
+                    self.cleanup_queue_len.fetch_add(1, Ordering::Relaxed);
+                }
+                *count = count.saturating_add(1);
+                self.cleanup_deferred_releases
+                    .fetch_add(1, Ordering::Relaxed);
+            }
            Err(poisoned) => {
                let mut queue = poisoned.into_inner();
-                queue.push((user.clone(), ip));
+                let count = queue.entry((user.clone(), ip)).or_insert(0);
+                if *count == 0 {
+                    self.cleanup_queue_len.fetch_add(1, Ordering::Relaxed);
+                }
+                *count = count.saturating_add(1);
+                self.cleanup_deferred_releases
+                    .fetch_add(1, Ordering::Relaxed);
                self.cleanup_queue.clear_poison();
                tracing::warn!(
                    "UserIpTracker cleanup_queue lock poisoned; recovered and enqueued IP cleanup for {} ({})",
@@ -75,21 +157,38 @@ impl UserIpTracker {
    }

    #[cfg(test)]
-    pub(crate) fn cleanup_queue_mutex_for_tests(&self) -> Arc<Mutex<Vec<(String, IpAddr)>>> {
+    pub(crate) fn cleanup_queue_mutex_for_tests(
+        &self,
+    ) -> Arc<Mutex<HashMap<(String, IpAddr), usize>>> {
        Arc::clone(&self.cleanup_queue)
    }

    pub(crate) async fn drain_cleanup_queue(&self) {
-        // Serialize queue draining and active-IP mutation so check-and-add cannot
-        // observe stale active entries that are already queued for removal.
-        let _drain_guard = self.cleanup_drain_lock.lock().await;
+        if self.cleanup_queue_len.load(Ordering::Relaxed) == 0 {
+            return;
+        }
+        let Ok(_drain_guard) = self.cleanup_drain_lock.try_lock() else {
+            return;
+        };
+
        let to_remove = {
            match self.cleanup_queue.lock() {
                Ok(mut queue) => {
                    if queue.is_empty() {
                        return;
                    }
-                    std::mem::take(&mut *queue)
+                    let mut drained =
+                        HashMap::with_capacity(queue.len().min(CLEANUP_DRAIN_BATCH_LIMIT));
+                    for _ in 0..CLEANUP_DRAIN_BATCH_LIMIT {
+                        let Some(key) = queue.keys().next().cloned() else {
+                            break;
+                        };
+                        if let Some(count) = queue.remove(&key) {
+                            self.cleanup_queue_len.fetch_sub(1, Ordering::Relaxed);
+                            drained.insert(key, count);
+                        }
+                    }
+                    drained
                }
                Err(poisoned) => {
                    let mut queue = poisoned.into_inner();
@@ -97,28 +196,34 @@ impl UserIpTracker {
                        self.cleanup_queue.clear_poison();
                        return;
                    }
-                    let drained = std::mem::take(&mut *queue);
+                    let mut drained =
+                        HashMap::with_capacity(queue.len().min(CLEANUP_DRAIN_BATCH_LIMIT));
+                    for _ in 0..CLEANUP_DRAIN_BATCH_LIMIT {
+                        let Some(key) = queue.keys().next().cloned() else {
+                            break;
+                        };
+                        if let Some(count) = queue.remove(&key) {
+                            self.cleanup_queue_len.fetch_sub(1, Ordering::Relaxed);
+                            drained.insert(key, count);
+                        }
+                    }
                    self.cleanup_queue.clear_poison();
                    drained
                }
            }
        };
+        if to_remove.is_empty() {
+            return;
+        }

        let mut active_ips = self.active_ips.write().await;
-        for (user, ip) in to_remove {
-            if let Some(user_ips) = active_ips.get_mut(&user) {
-                if let Some(count) = user_ips.get_mut(&ip) {
-                    if *count > 1 {
-                        *count -= 1;
-                    } else {
-                        user_ips.remove(&ip);
-                    }
-                }
-                if user_ips.is_empty() {
-                    active_ips.remove(&user);
-                }
-            }
+        let mut removed_active_entries = 0usize;
+        for ((user, ip), pending_count) in to_remove {
+            removed_active_entries = removed_active_entries.saturating_add(
+                Self::apply_active_cleanup(&mut active_ips, &user, ip, pending_count),
+            );
        }
+        Self::decrement_counter(&self.active_entry_count, removed_active_entries);
    }

    fn now_epoch_secs() -> u64 {
@@ -128,6 +233,24 @@ impl UserIpTracker {
            .as_secs()
    }

+    async fn active_and_recent_write(
+        &self,
+    ) -> (
+        RwLockWriteGuard<'_, HashMap<String, HashMap<IpAddr, usize>>>,
+        RwLockWriteGuard<'_, HashMap<String, HashMap<IpAddr, Instant>>>,
+    ) {
+        loop {
+            let active_ips = self.active_ips.write().await;
+            match self.recent_ips.try_write() {
+                Ok(recent_ips) => return (active_ips, recent_ips),
+                Err(_) => {
+                    drop(active_ips);
+                    tokio::task::yield_now().await;
+                }
+            }
+        }
+    }
+
    async fn maybe_compact_empty_users(&self) {
        const COMPACT_INTERVAL_SECS: u64 = 60;
        let now_epoch_secs = Self::now_epoch_secs();
@@ -148,14 +271,16 @@ impl UserIpTracker {
            return;
        }

-        let mut active_ips = self.active_ips.write().await;
-        let mut recent_ips = self.recent_ips.write().await;
        let window = *self.limit_window.read().await;
        let now = Instant::now();
+        let (mut active_ips, mut recent_ips) = self.active_and_recent_write().await;

+        let mut pruned_recent_entries = 0usize;
        for user_recent in recent_ips.values_mut() {
-            Self::prune_recent(user_recent, now, window);
+            pruned_recent_entries =
+                pruned_recent_entries.saturating_add(Self::prune_recent(user_recent, now, window));
        }
+        Self::decrement_counter(&self.recent_entry_count, pruned_recent_entries);

        let mut users =
            Vec::<String>::with_capacity(active_ips.len().saturating_add(recent_ips.len()));
@@ -182,12 +307,17 @@ impl UserIpTracker {
        }
    }

+    pub async fn run_periodic_maintenance(self: Arc<Self>) {
+        let mut interval = tokio::time::interval(Duration::from_secs(1));
+        loop {
+            interval.tick().await;
+            self.drain_cleanup_queue().await;
+            self.maybe_compact_empty_users().await;
+        }
+    }
+
    pub async fn memory_stats(&self) -> UserIpTrackerMemoryStats {
-        let cleanup_queue_len = self
-            .cleanup_queue
-            .lock()
-            .unwrap_or_else(|poisoned| poisoned.into_inner())
-            .len();
+        let cleanup_queue_len = self.cleanup_queue_len.load(Ordering::Relaxed) as usize;
        let active_ips = self.active_ips.read().await;
        let recent_ips = self.recent_ips.read().await;
        let active_entries = active_ips.values().map(HashMap::len).sum();
@@ -199,6 +329,9 @@ impl UserIpTracker {
            active_entries,
            recent_entries,
            cleanup_queue_len,
+            active_cap_rejects: self.active_cap_rejects.load(Ordering::Relaxed),
+            recent_cap_rejects: self.recent_cap_rejects.load(Ordering::Relaxed),
+            cleanup_deferred_releases: self.cleanup_deferred_releases.load(Ordering::Relaxed),
        }
    }

@@ -229,11 +362,17 @@ impl UserIpTracker {
        max_ips.clone_from(limits);
    }

-    fn prune_recent(user_recent: &mut HashMap<IpAddr, Instant>, now: Instant, window: Duration) {
+    fn prune_recent(
+        user_recent: &mut HashMap<IpAddr, Instant>,
+        now: Instant,
+        window: Duration,
+    ) -> usize {
        if user_recent.is_empty() {
-            return;
+            return 0;
        }
+        let before = user_recent.len();
        user_recent.retain(|_, seen_at| now.duration_since(*seen_at) <= window);
+        before.saturating_sub(user_recent.len())
    }

    pub async fn check_and_add(&self, username: &str, ip: IpAddr) -> Result<(), String> {
@@ -252,26 +391,40 @@ impl UserIpTracker {
        let window = *self.limit_window.read().await;
        let now = Instant::now();

-        let mut active_ips = self.active_ips.write().await;
+        let (mut active_ips, mut recent_ips) = self.active_and_recent_write().await;
        let user_active = active_ips
            .entry(username.to_string())
            .or_insert_with(HashMap::new);
-
-        let mut recent_ips = self.recent_ips.write().await;
        let user_recent = recent_ips
            .entry(username.to_string())
            .or_insert_with(HashMap::new);
-        Self::prune_recent(user_recent, now, window);
+        let pruned_recent_entries = Self::prune_recent(user_recent, now, window);
+        Self::decrement_counter(&self.recent_entry_count, pruned_recent_entries);
+        let recent_contains_ip = user_recent.contains_key(&ip);

        if let Some(count) = user_active.get_mut(&ip) {
+            if !recent_contains_ip
+                && self.recent_entry_count.load(Ordering::Relaxed) >= MAX_RECENT_IP_ENTRIES
+            {
+                self.recent_cap_rejects.fetch_add(1, Ordering::Relaxed);
+                return Err(format!(
+                    "IP tracker recent entry cap reached: entries={}/{}",
+                    self.recent_entry_count.load(Ordering::Relaxed),
+                    MAX_RECENT_IP_ENTRIES
+                ));
+            }
            *count = count.saturating_add(1);
-            user_recent.insert(ip, now);
+            if user_recent.insert(ip, now).is_none() {
+                self.recent_entry_count.fetch_add(1, Ordering::Relaxed);
+            }
            return Ok(());
        }

+        let is_new_ip = !recent_contains_ip;
+
        if let Some(limit) = limit {
            let active_limit_reached = user_active.len() >= limit;
-            let recent_limit_reached = user_recent.len() >= limit;
+            let recent_limit_reached = user_recent.len() >= limit && is_new_ip;
            let deny = match mode {
                UserMaxUniqueIpsMode::ActiveWindow => active_limit_reached,
                UserMaxUniqueIpsMode::TimeWindow => recent_limit_reached,
@@ -291,30 +444,62 @@ impl UserIpTracker {
            }
        }

-        user_active.insert(ip, 1);
-        user_recent.insert(ip, now);
+        if self.active_entry_count.load(Ordering::Relaxed) >= MAX_ACTIVE_IP_ENTRIES {
+            self.active_cap_rejects.fetch_add(1, Ordering::Relaxed);
+            return Err(format!(
+                "IP tracker active entry cap reached: entries={}/{}",
+                self.active_entry_count.load(Ordering::Relaxed),
+                MAX_ACTIVE_IP_ENTRIES
+            ));
+        }
+        if is_new_ip && self.recent_entry_count.load(Ordering::Relaxed) >= MAX_RECENT_IP_ENTRIES {
+            self.recent_cap_rejects.fetch_add(1, Ordering::Relaxed);
+            return Err(format!(
+                "IP tracker recent entry cap reached: entries={}/{}",
+                self.recent_entry_count.load(Ordering::Relaxed),
+                MAX_RECENT_IP_ENTRIES
+            ));
+        }
+
+        if user_active.insert(ip, 1).is_none() {
+            self.active_entry_count.fetch_add(1, Ordering::Relaxed);
+        }
+        if user_recent.insert(ip, now).is_none() {
+            self.recent_entry_count.fetch_add(1, Ordering::Relaxed);
+        }
        Ok(())
    }

    pub async fn remove_ip(&self, username: &str, ip: IpAddr) {
        self.maybe_compact_empty_users().await;
        let mut active_ips = self.active_ips.write().await;
+        let mut removed_active_entries = 0usize;
        if let Some(user_ips) = active_ips.get_mut(username) {
            if let Some(count) = user_ips.get_mut(&ip) {
                if *count > 1 {
                    *count -= 1;
                } else {
-                    user_ips.remove(&ip);
+                    if user_ips.remove(&ip).is_some() {
+                        removed_active_entries = 1;
+                    }
                }
            }
            if user_ips.is_empty() {
                active_ips.remove(username);
            }
        }
+        Self::decrement_counter(&self.active_entry_count, removed_active_entries);
    }

    pub async fn get_recent_counts_for_users(&self, users: &[String]) -> HashMap<String, usize> {
        self.drain_cleanup_queue().await;
+        self.get_recent_counts_for_users_snapshot(users).await
+    }
+
+    pub(crate) async fn get_recent_counts_for_users_snapshot(
+        &self,
+        users: &[String],
+    ) -> HashMap<String, usize> {
        let window = *self.limit_window.read().await;
        let now = Instant::now();
        let recent_ips = self.recent_ips.read().await;
@@ -389,19 +574,29 @@ impl UserIpTracker {

    pub async fn get_stats(&self) -> Vec<(String, usize, usize)> {
        self.drain_cleanup_queue().await;
+        self.get_stats_snapshot().await
+    }
+
+    pub(crate) async fn get_stats_snapshot(&self) -> Vec<(String, usize, usize)> {
        let active_ips = self.active_ips.read().await;
+        let active_counts = active_ips
+            .iter()
+            .map(|(username, user_ips)| (username.clone(), user_ips.len()))
+            .collect::<Vec<_>>();
+        drop(active_ips);
+
        let max_ips = self.max_ips.read().await;
        let default_max_ips = *self.default_max_ips.read().await;

-        let mut stats = Vec::new();
-        for (username, user_ips) in active_ips.iter() {
+        let mut stats = Vec::with_capacity(active_counts.len());
+        for (username, active_count) in active_counts {
            let limit = max_ips
-                .get(username)
+                .get(&username)
                .copied()
                .filter(|limit| *limit > 0)
                .or((default_max_ips > 0).then_some(default_max_ips))
                .unwrap_or(0);
-            stats.push((username.clone(), user_ips.len(), limit));
+            stats.push((username, active_count, limit));
        }

        stats.sort_by(|a, b| a.0.cmp(&b.0));
@@ -410,20 +605,30 @@ impl UserIpTracker {

    pub async fn clear_user_ips(&self, username: &str) {
        let mut active_ips = self.active_ips.write().await;
-        active_ips.remove(username);
+        let removed_active_entries = active_ips
+            .remove(username)
+            .map(|ips| ips.len())
+            .unwrap_or(0);
        drop(active_ips);
+        Self::decrement_counter(&self.active_entry_count, removed_active_entries);

        let mut recent_ips = self.recent_ips.write().await;
-        recent_ips.remove(username);
+        let removed_recent_entries = recent_ips
+            .remove(username)
+            .map(|ips| ips.len())
+            .unwrap_or(0);
+        Self::decrement_counter(&self.recent_entry_count, removed_recent_entries);
    }

    pub async fn clear_all(&self) {
        let mut active_ips = self.active_ips.write().await;
        active_ips.clear();
        drop(active_ips);
+        self.active_entry_count.store(0, Ordering::Relaxed);

        let mut recent_ips = self.recent_ips.write().await;
        recent_ips.clear();
+        self.recent_entry_count.store(0, Ordering::Relaxed);
    }

    pub async fn is_ip_active(&self, username: &str, ip: IpAddr) -> bool {
@@ -851,4 +1056,19 @@ mod tests {
            .unwrap_or(false);
        assert!(!stale_exists);
    }
+
+    #[tokio::test]
+    async fn test_time_window_allows_same_ip_reconnect() {
+        let tracker = UserIpTracker::new();
+        tracker.set_user_limit("test_user", 1).await;
+        tracker
+            .set_limit_policy(UserMaxUniqueIpsMode::TimeWindow, 1)
+            .await;
+
+        let ip1 = test_ipv4(10, 4, 0, 1);
+
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        tracker.remove_ip("test_user", ip1).await;
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+    }
 }
--- a/src/maestro/admission.rs
+++ b/src/maestro/admission.rs
@@ -17,6 +17,7 @@ pub(crate) async fn configure_admission_gate(
    route_runtime: Arc<RouteRuntimeController>,
    admission_tx: &watch::Sender<bool>,
    config_rx: watch::Receiver<Arc<ProxyConfig>>,
+    me_ready_rx: watch::Receiver<u64>,
 ) {
    if config.general.use_middle_proxy {
        if let Some(pool) = me_pool.as_ref() {
@@ -52,6 +53,7 @@ pub(crate) async fn configure_admission_gate(
            let admission_tx_gate = admission_tx.clone();
            let route_runtime_gate = route_runtime.clone();
            let mut config_rx_gate = config_rx.clone();
+            let mut me_ready_rx_gate = me_ready_rx;
            let mut admission_poll_ms = config.general.me_admission_poll_ms.max(1);
            tokio::spawn(async move {
                let mut gate_open = initial_gate_open;
@@ -74,6 +76,11 @@ pub(crate) async fn configure_admission_gate(
                            fast_fallback_enabled = cfg.general.me2dc_fallback && cfg.general.me2dc_fast;
                            continue;
                        }
+                        changed = me_ready_rx_gate.changed() => {
+                            if changed.is_err() {
+                                break;
+                            }
+                        }
                        _ = tokio::time::sleep(Duration::from_millis(admission_poll_ms)) => {}
                    }
                    let ready = pool_for_gate.admission_ready_conditional_cast().await;
--- a/src/maestro/helpers.rs
+++ b/src/maestro/helpers.rs
@@ -1,6 +1,6 @@
 #![allow(clippy::items_after_test_module)]

-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::time::Duration;

 use tokio::sync::watch;
@@ -17,7 +17,7 @@ use crate::transport::middle_proxy::{

 pub(crate) fn resolve_runtime_config_path(
    config_path_cli: &str,
-    startup_cwd: &std::path::Path,
+    startup_cwd: &Path,
    config_path_explicit: bool,
 ) -> PathBuf {
    if config_path_explicit {
@@ -46,6 +46,39 @@ pub(crate) fn resolve_runtime_config_path(
    startup_cwd.join("config.toml")
 }

+pub(crate) fn resolve_runtime_base_dir(
+    config_path: &Path,
+    startup_cwd: &Path,
+    config_path_explicit: bool,
+    data_path: Option<&Path>,
+) -> PathBuf {
+    if let Some(path) = data_path {
+        return normalize_runtime_dir(path, startup_cwd);
+    }
+
+    if startup_cwd != Path::new("/") {
+        return normalize_runtime_dir(startup_cwd, startup_cwd);
+    }
+
+    if config_path_explicit
+        && let Some(parent) = config_path.parent()
+        && !parent.as_os_str().is_empty()
+    {
+        return normalize_runtime_dir(parent, startup_cwd);
+    }
+
+    PathBuf::from("/etc/telemt")
+}
+
+fn normalize_runtime_dir(path: &Path, startup_cwd: &Path) -> PathBuf {
+    let absolute = if path.is_absolute() {
+        path.to_path_buf()
+    } else {
+        startup_cwd.join(path)
+    };
+    absolute.canonicalize().unwrap_or(absolute)
+}
+
 /// Parsed CLI arguments.
 pub(crate) struct CliArgs {
    pub config_path: String,
@@ -231,9 +264,11 @@ fn print_help() {

 #[cfg(test)]
 mod tests {
+    use std::path::{Path, PathBuf};
+
    use super::{
        expected_handshake_close_description, is_expected_handshake_eof, peer_close_description,
-        resolve_runtime_config_path,
+        resolve_runtime_base_dir, resolve_runtime_config_path,
    };
    use crate::error::{ProxyError, StreamError};

@@ -304,6 +339,91 @@ mod tests {
        let _ = std::fs::remove_dir(&startup_cwd);
    }

+    #[test]
+    fn resolve_runtime_base_dir_prefers_cli_data_path() {
+        let nonce = std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap()
+            .as_nanos();
+        let startup_cwd = std::env::temp_dir().join(format!("telemt_runtime_base_cwd_{nonce}"));
+        let data_path = std::env::temp_dir().join(format!("telemt_runtime_base_data_{nonce}"));
+        std::fs::create_dir_all(&startup_cwd).unwrap();
+        std::fs::create_dir_all(&data_path).unwrap();
+
+        let resolved = resolve_runtime_base_dir(
+            &startup_cwd.join("config.toml"),
+            &startup_cwd,
+            true,
+            Some(&data_path),
+        );
+        assert_eq!(resolved, data_path.canonicalize().unwrap());
+
+        let _ = std::fs::remove_dir(&data_path);
+        let _ = std::fs::remove_dir(&startup_cwd);
+    }
+
+    #[test]
+    fn resolve_runtime_base_dir_uses_working_directory_before_explicit_config_parent() {
+        let nonce = std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap()
+            .as_nanos();
+        let startup_cwd = std::env::temp_dir().join(format!("telemt_runtime_base_start_{nonce}"));
+        let config_dir = std::env::temp_dir().join(format!("telemt_runtime_base_cfg_{nonce}"));
+        std::fs::create_dir_all(&startup_cwd).unwrap();
+        std::fs::create_dir_all(&config_dir).unwrap();
+
+        let resolved =
+            resolve_runtime_base_dir(&config_dir.join("telemt.toml"), &startup_cwd, true, None);
+        assert_eq!(resolved, startup_cwd.canonicalize().unwrap());
+
+        let _ = std::fs::remove_dir(&config_dir);
+        let _ = std::fs::remove_dir(&startup_cwd);
+    }
+
+    #[test]
+    fn resolve_runtime_base_dir_uses_explicit_config_parent_from_root() {
+        let nonce = std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap()
+            .as_nanos();
+        let config_dir = std::env::temp_dir().join(format!("telemt_runtime_base_root_cfg_{nonce}"));
+        std::fs::create_dir_all(&config_dir).unwrap();
+
+        let resolved =
+            resolve_runtime_base_dir(&config_dir.join("telemt.toml"), Path::new("/"), true, None);
+        assert_eq!(resolved, config_dir.canonicalize().unwrap());
+
+        let _ = std::fs::remove_dir(&config_dir);
+    }
+
+    #[test]
+    fn resolve_runtime_base_dir_uses_systemd_working_directory_before_etc() {
+        let nonce = std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap()
+            .as_nanos();
+        let startup_cwd = std::env::temp_dir().join(format!("telemt_runtime_base_systemd_{nonce}"));
+        std::fs::create_dir_all(&startup_cwd).unwrap();
+
+        let resolved =
+            resolve_runtime_base_dir(&startup_cwd.join("config.toml"), &startup_cwd, false, None);
+        assert_eq!(resolved, startup_cwd.canonicalize().unwrap());
+
+        let _ = std::fs::remove_dir(&startup_cwd);
+    }
+
+    #[test]
+    fn resolve_runtime_base_dir_falls_back_to_etc_from_root() {
+        let resolved = resolve_runtime_base_dir(
+            Path::new("/etc/telemt/config.toml"),
+            Path::new("/"),
+            false,
+            None,
+        );
+        assert_eq!(resolved, PathBuf::from("/etc/telemt"));
+    }
+
    #[test]
    fn expected_handshake_eof_matches_connection_reset() {
        let err = ProxyError::Io(std::io::Error::from(std::io::ErrorKind::ConnectionReset));
--- a/src/maestro/listeners.rs
+++ b/src/maestro/listeners.rs
@@ -13,7 +13,7 @@ use crate::config::{ProxyConfig, RstOnCloseMode};
 use crate::crypto::SecureRandom;
 use crate::ip_tracker::UserIpTracker;
 use crate::proxy::ClientHandler;
-use crate::proxy::route_mode::{ROUTE_SWITCH_ERROR_MSG, RouteRuntimeController};
+use crate::proxy::route_mode::RouteRuntimeController;
 use crate::proxy::shared_state::ProxySharedState;
 use crate::startup::{COMPONENT_LISTENERS_BIND, StartupTracker};
 use crate::stats::beobachten::BeobachtenStore;
@@ -492,14 +492,10 @@ pub(crate) fn spawn_tcp_accept_loops(
                                let handshake_close_reason =
                                    expected_handshake_close_description(&e);

-                                let me_closed = matches!(
-                                    &e,
-                                    crate::error::ProxyError::Proxy(msg) if msg == "ME connection lost"
-                                );
-                                let route_switched = matches!(
-                                    &e,
-                                    crate::error::ProxyError::Proxy(msg) if msg == ROUTE_SWITCH_ERROR_MSG
-                                );
+                                let me_closed =
+                                    matches!(&e, crate::error::ProxyError::MiddleConnectionLost);
+                                let route_switched =
+                                    matches!(&e, crate::error::ProxyError::RouteSwitched);

                                match (peer_close_reason, me_closed) {
                                    (Some(reason), _) => {
--- a/src/maestro/me_startup.rs
+++ b/src/maestro/me_startup.rs
@@ -3,7 +3,7 @@
 use std::sync::Arc;
 use std::time::Duration;

-use tokio::sync::RwLock;
+use tokio::sync::{RwLock, watch};
 use tracing::{error, info, warn};

 use crate::config::ProxyConfig;
@@ -29,6 +29,7 @@ pub(crate) async fn initialize_me_pool(
    rng: Arc<SecureRandom>,
    stats: Arc<Stats>,
    api_me_pool: Arc<RwLock<Option<Arc<MePool>>>>,
+    me_ready_tx: watch::Sender<u64>,
 ) -> Option<Arc<MePool>> {
    if !use_middle_proxy {
        return None;
@@ -314,6 +315,7 @@ pub(crate) async fn initialize_me_pool(
                    let pool_bg = pool.clone();
                    let rng_bg = rng.clone();
                    let startup_tracker_bg = startup_tracker.clone();
+                    let me_ready_tx_bg = me_ready_tx.clone();
                    let retry_limit = if me_init_retry_attempts == 0 {
                        String::from("unlimited")
                    } else {
@@ -347,6 +349,9 @@ pub(crate) async fn initialize_me_pool(
                                        startup_tracker_bg
                                            .set_me_status(StartupMeStatus::Ready, "ready")
                                            .await;
+                                        me_ready_tx_bg.send_modify(|version| {
+                                            *version = version.saturating_add(1);
+                                        });
                                        info!(
                                            attempt = init_attempt,
                                            "Middle-End pool initialized successfully"
@@ -474,6 +479,9 @@ pub(crate) async fn initialize_me_pool(
                                startup_tracker
                                    .set_me_status(StartupMeStatus::Ready, "ready")
                                    .await;
+                                me_ready_tx.send_modify(|version| {
+                                    *version = version.saturating_add(1);
+                                });
                                info!(
                                    attempt = init_attempt,
                                    "Middle-End pool initialized successfully"
--- a/src/maestro/mod.rs
+++ b/src/maestro/mod.rs
@@ -47,7 +47,7 @@ use crate::stats::{ReplayChecker, Stats};
 use crate::stream::BufferPool;
 use crate::transport::UpstreamManager;
 use crate::transport::middle_proxy::MePool;
-use helpers::{parse_cli, resolve_runtime_config_path};
+use helpers::{parse_cli, resolve_runtime_base_dir, resolve_runtime_config_path};

 #[cfg(unix)]
 use crate::daemon::{DaemonOptions, PidFile, drop_privileges};
@@ -112,8 +112,51 @@ async fn run_telemt_core(
            std::process::exit(1);
        }
    };
+    if let Some(ref data_path) = data_path
+        && !data_path.is_absolute()
+    {
+        eprintln!(
+            "[telemt] data_path must be absolute: {}",
+            data_path.display()
+        );
+        std::process::exit(1);
+    }
    let mut config_path =
        resolve_runtime_config_path(&config_path_cli, &startup_cwd, config_path_explicit);
+    let runtime_base_dir = resolve_runtime_base_dir(
+        &config_path,
+        &startup_cwd,
+        config_path_explicit,
+        data_path.as_deref(),
+    );
+
+    if !runtime_base_dir.exists()
+        && let Err(e) = std::fs::create_dir_all(&runtime_base_dir)
+    {
+        eprintln!(
+            "[telemt] Can't create runtime directory {}: {}",
+            runtime_base_dir.display(),
+            e
+        );
+        std::process::exit(1);
+    }
+
+    if !runtime_base_dir.is_dir() {
+        eprintln!(
+            "[telemt] Runtime path exists but is not a directory: {}",
+            runtime_base_dir.display()
+        );
+        std::process::exit(1);
+    }
+
+    if let Err(e) = std::env::set_current_dir(&runtime_base_dir) {
+        eprintln!(
+            "[telemt] Can't use runtime directory {}: {}",
+            runtime_base_dir.display(),
+            e
+        );
+        std::process::exit(1);
+    }

    let mut config = match ProxyConfig::load(&config_path) {
        Ok(c) => c,
@@ -156,16 +199,15 @@ async fn run_telemt_core(
                        );
                    }
                } else {
-                    let system_dir = std::path::Path::new("/etc/telemt");
-                    let system_config_path = system_dir.join("telemt.toml");
-                    let startup_config_path = startup_cwd.join("config.toml");
+                    let runtime_config_path = runtime_base_dir.join("telemt.toml");
+                    let fallback_config_path = runtime_base_dir.join("config.toml");
                    let mut persisted = false;

                    if let Some(serialized) = serialized.as_ref() {
-                        match std::fs::create_dir_all(system_dir) {
-                            Ok(()) => match std::fs::write(&system_config_path, serialized) {
+                        match std::fs::create_dir_all(&runtime_base_dir) {
+                            Ok(()) => match std::fs::write(&runtime_config_path, serialized) {
                                Ok(()) => {
-                                    config_path = system_config_path;
+                                    config_path = runtime_config_path;
                                    eprintln!(
                                        "[telemt] Created default config at {}",
                                        config_path.display()
@@ -175,7 +217,7 @@ async fn run_telemt_core(
                                Err(write_error) => {
                                    eprintln!(
                                        "[telemt] Warning: failed to write default config at {}: {}",
-                                        system_config_path.display(),
+                                        runtime_config_path.display(),
                                        write_error
                                    );
                                }
@@ -183,16 +225,16 @@ async fn run_telemt_core(
                            Err(create_error) => {
                                eprintln!(
                                    "[telemt] Warning: failed to create {}: {}",
-                                    system_dir.display(),
+                                    runtime_base_dir.display(),
                                    create_error
                                );
                            }
                        }

                        if !persisted {
-                            match std::fs::write(&startup_config_path, serialized) {
+                            match std::fs::write(&fallback_config_path, serialized) {
                                Ok(()) => {
-                                    config_path = startup_config_path;
+                                    config_path = fallback_config_path;
                                    eprintln!(
                                        "[telemt] Created default config at {}",
                                        config_path.display()
@@ -202,7 +244,7 @@ async fn run_telemt_core(
                                Err(write_error) => {
                                    eprintln!(
                                        "[telemt] Warning: failed to write default config at {}: {}",
-                                        startup_config_path.display(),
+                                        fallback_config_path.display(),
                                        write_error
                                    );
                                }
@@ -375,6 +417,8 @@ async fn run_telemt_core(

    let stats = Arc::new(Stats::new());
    stats.apply_telemetry_policy(TelemetryPolicy::from_config(&config.general.telemetry));
+    let quota_state_path = config.general.quota_state_path.clone();
+    crate::quota_state::load_quota_state(&quota_state_path, stats.as_ref()).await;

    let upstream_manager = Arc::new(UpstreamManager::new(
        config.upstreams.clone(),
@@ -454,6 +498,7 @@ async fn run_telemt_core(
            let config_rx_api = api_config_rx.clone();
            let admission_rx_api = admission_rx.clone();
            let config_path_api = config_path.clone();
+            let quota_state_path_api = quota_state_path.clone();
            let startup_tracker_api = startup_tracker.clone();
            let detected_ips_rx_api = detected_ips_rx.clone();
            tokio::spawn(async move {
@@ -467,6 +512,7 @@ async fn run_telemt_core(
                    config_rx_api,
                    admission_rx_api,
                    config_path_api,
+                    quota_state_path_api,
                    detected_ips_rx_api,
                    process_started_at_epoch_secs,
                    startup_tracker_api,
@@ -618,6 +664,8 @@ async fn run_telemt_core(
            .await;
    }

+    let (me_ready_tx, me_ready_rx) = watch::channel(0_u64);
+
    let me_pool: Option<Arc<MePool>> = me_startup::initialize_me_pool(
        use_middle_proxy,
        &config,
@@ -628,6 +676,7 @@ async fn run_telemt_core(
        rng.clone(),
        stats.clone(),
        api_me_pool.clone(),
+        me_ready_tx.clone(),
    )
    .await;

@@ -701,6 +750,7 @@ async fn run_telemt_core(
        api_config_tx.clone(),
        me_pool.clone(),
        shared_state.clone(),
+        me_ready_tx.clone(),
    )
    .await;
    let config_rx = runtime_watches.config_rx;
@@ -714,6 +764,7 @@ async fn run_telemt_core(
        route_runtime.clone(),
        &admission_tx,
        config_rx.clone(),
+        me_ready_rx,
    )
    .await;
    let _admission_tx_hold = admission_tx;
@@ -772,6 +823,7 @@ async fn run_telemt_core(
        beobachten.clone(),
        shared_state.clone(),
        ip_tracker.clone(),
+        tls_cache.clone(),
        config_rx.clone(),
    )
    .await;
@@ -799,7 +851,7 @@ async fn run_telemt_core(
        max_connections.clone(),
    );

-    shutdown::wait_for_shutdown(process_started_at, me_pool, stats).await;
+    shutdown::wait_for_shutdown(process_started_at, me_pool, stats, quota_state_path).await;

    Ok(())
 }
--- a/src/maestro/runtime_tasks.rs
+++ b/src/maestro/runtime_tasks.rs
@@ -21,6 +21,7 @@ use crate::startup::{
 use crate::stats::beobachten::BeobachtenStore;
 use crate::stats::telemetry::TelemetryPolicy;
 use crate::stats::{ReplayChecker, Stats};
+use crate::tls_front::TlsFrontCache;
 use crate::transport::UpstreamManager;
 use crate::transport::middle_proxy::{MePool, MeReinitTrigger};

@@ -52,6 +53,7 @@ pub(crate) async fn spawn_runtime_tasks(
    api_config_tx: watch::Sender<Arc<ProxyConfig>>,
    me_pool_for_policy: Option<Arc<MePool>>,
    shared_state: Arc<ProxySharedState>,
+    me_ready_tx: watch::Sender<u64>,
 ) -> RuntimeWatches {
    let um_clone = upstream_manager.clone();
    let dc_overrides_for_health = config.dc_overrides.clone();
@@ -71,6 +73,18 @@ pub(crate) async fn spawn_runtime_tasks(
        rc_clone.run_periodic_cleanup().await;
    });

+    let stats_maintenance = stats.clone();
+    tokio::spawn(async move {
+        stats_maintenance
+            .run_periodic_user_stats_maintenance()
+            .await;
+    });
+
+    let ip_tracker_maintenance = ip_tracker.clone();
+    tokio::spawn(async move {
+        ip_tracker_maintenance.run_periodic_maintenance().await;
+    });
+
    let detected_ip_v4: Option<IpAddr> = probe.detected_ipv4.map(IpAddr::V4);
    let detected_ip_v6: Option<IpAddr> = probe.detected_ipv6.map(IpAddr::V6);
    debug!(
@@ -249,12 +263,14 @@ pub(crate) async fn spawn_runtime_tasks(
        let pool_clone_sched = pool.clone();
        let rng_clone_sched = rng.clone();
        let config_rx_clone_sched = config_rx.clone();
+        let me_ready_tx_sched = me_ready_tx.clone();
        tokio::spawn(async move {
            crate::transport::middle_proxy::me_reinit_scheduler(
                pool_clone_sched,
                rng_clone_sched,
                config_rx_clone_sched,
                reinit_rx,
+                me_ready_tx_sched,
            )
            .await;
        });
@@ -328,6 +344,7 @@ pub(crate) async fn spawn_metrics_if_configured(
    beobachten: Arc<BeobachtenStore>,
    shared_state: Arc<ProxySharedState>,
    ip_tracker: Arc<UserIpTracker>,
+    tls_cache: Option<Arc<TlsFrontCache>>,
    config_rx: watch::Receiver<Arc<ProxyConfig>>,
 ) {
    // metrics_listen takes precedence; fall back to metrics_port for backward compat.
@@ -363,6 +380,7 @@ pub(crate) async fn spawn_metrics_if_configured(
        let shared_state = shared_state.clone();
        let config_rx_metrics = config_rx.clone();
        let ip_tracker_metrics = ip_tracker.clone();
+        let tls_cache_metrics = tls_cache.clone();
        let whitelist = config.server.metrics_whitelist.clone();
        let listen_backlog = config.server.listen_backlog;
        tokio::spawn(async move {
@@ -374,6 +392,7 @@ pub(crate) async fn spawn_metrics_if_configured(
                beobachten,
                shared_state,
                ip_tracker_metrics,
+                tls_cache_metrics,
                config_rx_metrics,
                whitelist,
            )
--- a/src/maestro/shutdown.rs
+++ b/src/maestro/shutdown.rs
@@ -8,6 +8,7 @@
 //!
 //! SIGHUP is handled separately in config/hot_reload.rs for config reload.

+use std::path::PathBuf;
 use std::sync::Arc;
 use std::time::{Duration, Instant};

@@ -48,9 +49,17 @@ pub(crate) async fn wait_for_shutdown(
    process_started_at: Instant,
    me_pool: Option<Arc<MePool>>,
    stats: Arc<Stats>,
+    quota_state_path: PathBuf,
 ) {
    let signal = wait_for_shutdown_signal().await;
-    perform_shutdown(signal, process_started_at, me_pool, &stats).await;
+    perform_shutdown(
+        signal,
+        process_started_at,
+        me_pool,
+        &stats,
+        quota_state_path,
+    )
+    .await;
 }

 /// Waits for any shutdown signal (SIGINT, SIGTERM, SIGQUIT).
@@ -79,6 +88,7 @@ async fn perform_shutdown(
    process_started_at: Instant,
    me_pool: Option<Arc<MePool>>,
    stats: &Stats,
+    quota_state_path: PathBuf,
 ) {
    let shutdown_started_at = Instant::now();
    info!(signal = %signal, "Received shutdown signal");
@@ -109,6 +119,22 @@ async fn perform_shutdown(
        }
    }

+    match crate::quota_state::save_quota_state(&quota_state_path, stats).await {
+        Ok(()) => {
+            info!(
+                path = %quota_state_path.display(),
+                "Persisted per-user quota state"
+            );
+        }
+        Err(error) => {
+            warn!(
+                error = %error,
+                path = %quota_state_path.display(),
+                "Failed to persist per-user quota state"
+            );
+        }
+    }
+
    let shutdown_secs = shutdown_started_at.elapsed().as_secs();
    info!(
        "Shutdown completed successfully in {} {}.",
--- a/src/maestro/tls_bootstrap.rs
+++ b/src/maestro/tls_bootstrap.rs
@@ -10,6 +10,14 @@ use crate::tls_front::TlsFrontCache;
 use crate::tls_front::fetcher::TlsFetchStrategy;
 use crate::transport::UpstreamManager;

+fn tls_fetch_host_for_domain(mask_host: &str, primary_tls_domain: &str, domain: &str) -> String {
+    if mask_host.eq_ignore_ascii_case(primary_tls_domain) {
+        domain.to_string()
+    } else {
+        mask_host.to_string()
+    }
+}
+
 pub(crate) async fn bootstrap_tls_front(
    config: &ProxyConfig,
    tls_domains: &[String],
@@ -56,6 +64,7 @@ pub(crate) async fn bootstrap_tls_front(
        let cache_initial = cache.clone();
        let domains_initial = tls_domains.to_vec();
        let host_initial = mask_host.clone();
+        let primary_initial = config.censorship.tls_domain.clone();
        let unix_sock_initial = mask_unix_sock.clone();
        let scope_initial = tls_fetch_scope.clone();
        let upstream_initial = upstream_manager.clone();
@@ -64,7 +73,8 @@ pub(crate) async fn bootstrap_tls_front(
            let mut join = tokio::task::JoinSet::new();
            for domain in domains_initial {
                let cache_domain = cache_initial.clone();
-                let host_domain = host_initial.clone();
+                let host_domain =
+                    tls_fetch_host_for_domain(&host_initial, &primary_initial, &domain);
                let unix_sock_domain = unix_sock_initial.clone();
                let scope_domain = scope_initial.clone();
                let upstream_domain = upstream_initial.clone();
@@ -117,6 +127,7 @@ pub(crate) async fn bootstrap_tls_front(
        let cache_refresh = cache.clone();
        let domains_refresh = tls_domains.to_vec();
        let host_refresh = mask_host.clone();
+        let primary_refresh = config.censorship.tls_domain.clone();
        let unix_sock_refresh = mask_unix_sock.clone();
        let scope_refresh = tls_fetch_scope.clone();
        let upstream_refresh = upstream_manager.clone();
@@ -130,7 +141,8 @@ pub(crate) async fn bootstrap_tls_front(
                let mut join = tokio::task::JoinSet::new();
                for domain in domains_refresh.clone() {
                    let cache_domain = cache_refresh.clone();
-                    let host_domain = host_refresh.clone();
+                    let host_domain =
+                        tls_fetch_host_for_domain(&host_refresh, &primary_refresh, &domain);
                    let unix_sock_domain = unix_sock_refresh.clone();
                    let scope_domain = scope_refresh.clone();
                    let upstream_domain = upstream_refresh.clone();
@@ -186,3 +198,24 @@ pub(crate) async fn bootstrap_tls_front(

    tls_cache
 }
+
+#[cfg(test)]
+mod tests {
+    use super::tls_fetch_host_for_domain;
+
+    #[test]
+    fn tls_fetch_host_uses_each_domain_when_mask_host_is_primary_default() {
+        assert_eq!(
+            tls_fetch_host_for_domain("a.com", "a.com", "b.com"),
+            "b.com"
+        );
+    }
+
+    #[test]
+    fn tls_fetch_host_preserves_explicit_non_primary_mask_host() {
+        assert_eq!(
+            tls_fetch_host_for_domain("origin.example", "a.com", "b.com"),
+            "origin.example"
+        );
+    }
+}
--- a/src/main.rs
+++ b/src/main.rs
@@ -25,6 +25,7 @@ mod metrics;
 mod network;
 mod protocol;
 mod proxy;
+mod quota_state;
 mod service;
 mod startup;
 mod stats;
--- a/src/metrics.rs
+++ b/src/metrics.rs
@@ -11,6 +11,8 @@ use hyper::service::service_fn;
 use hyper::{Request, Response, StatusCode};
 use ipnetwork::IpNetwork;
 use tokio::net::TcpListener;
+use tokio::sync::Semaphore;
+use tokio::time::timeout;
 use tracing::{debug, info, warn};

 use crate::config::ProxyConfig;
@@ -18,8 +20,18 @@ use crate::ip_tracker::UserIpTracker;
 use crate::proxy::shared_state::ProxySharedState;
 use crate::stats::Stats;
 use crate::stats::beobachten::BeobachtenStore;
+use crate::tls_front::TlsFrontCache;
+use crate::tls_front::cache;
+use crate::tls_front::fetcher;
 use crate::transport::{ListenOptions, create_listener};

+// Keeps `/metrics` response size bounded when per-user telemetry is enabled.
+const USER_LABELED_METRICS_MAX_USERS: usize = 4096;
+// Keeps TLS-front per-domain health series bounded for large generated configs.
+const TLS_FRONT_PROFILE_HEALTH_MAX_DOMAINS: usize = 256;
+const METRICS_MAX_CONTROL_CONNECTIONS: usize = 512;
+const METRICS_HTTP_CONNECTION_TIMEOUT: Duration = Duration::from_secs(15);
+
 pub async fn serve(
    port: u16,
    listen: Option<String>,
@@ -28,6 +40,7 @@ pub async fn serve(
    beobachten: Arc<BeobachtenStore>,
    shared_state: Arc<ProxySharedState>,
    ip_tracker: Arc<UserIpTracker>,
+    tls_cache: Option<Arc<TlsFrontCache>>,
    config_rx: tokio::sync::watch::Receiver<Arc<ProxyConfig>>,
    whitelist: Vec<IpNetwork>,
 ) {
@@ -52,6 +65,7 @@ pub async fn serve(
                    beobachten,
                    shared_state,
                    ip_tracker,
+                    tls_cache,
                    config_rx,
                    whitelist,
                )
@@ -64,11 +78,11 @@ pub async fn serve(
        return;
    }

-    // Fallback: bind on 0.0.0.0 and [::] using metrics_port.
+    // Fallback: keep metrics local unless an explicit metrics_listen is configured.
    let mut listener_v4 = None;
    let mut listener_v6 = None;

-    let addr_v4 = SocketAddr::from(([0, 0, 0, 0], port));
+    let addr_v4 = SocketAddr::from(([127, 0, 0, 1], port));
    match bind_metrics_listener(addr_v4, false, listen_backlog) {
        Ok(listener) => {
            info!(
@@ -82,11 +96,11 @@ pub async fn serve(
        }
    }

-    let addr_v6 = SocketAddr::from(([0, 0, 0, 0, 0, 0, 0, 0], port));
+    let addr_v6 = SocketAddr::from(([0, 0, 0, 0, 0, 0, 0, 1], port));
    match bind_metrics_listener(addr_v6, true, listen_backlog) {
        Ok(listener) => {
            info!(
-                "Metrics endpoint: http://[::]:{}/metrics and /beobachten",
+                "Metrics endpoint: http://[::1]:{}/metrics and /beobachten",
                port
            );
            listener_v6 = Some(listener);
@@ -107,6 +121,7 @@ pub async fn serve(
                beobachten,
                shared_state,
                ip_tracker,
+                tls_cache,
                config_rx,
                whitelist,
            )
@@ -117,6 +132,7 @@ pub async fn serve(
            let beobachten_v6 = beobachten.clone();
            let shared_state_v6 = shared_state.clone();
            let ip_tracker_v6 = ip_tracker.clone();
+            let tls_cache_v6 = tls_cache.clone();
            let config_rx_v6 = config_rx.clone();
            let whitelist_v6 = whitelist.clone();
            tokio::spawn(async move {
@@ -126,6 +142,7 @@ pub async fn serve(
                    beobachten_v6,
                    shared_state_v6,
                    ip_tracker_v6,
+                    tls_cache_v6,
                    config_rx_v6,
                    whitelist_v6,
                )
@@ -137,6 +154,7 @@ pub async fn serve(
                beobachten,
                shared_state,
                ip_tracker,
+                tls_cache,
                config_rx,
                whitelist,
            )
@@ -166,9 +184,12 @@ async fn serve_listener(
    beobachten: Arc<BeobachtenStore>,
    shared_state: Arc<ProxySharedState>,
    ip_tracker: Arc<UserIpTracker>,
+    tls_cache: Option<Arc<TlsFrontCache>>,
    config_rx: tokio::sync::watch::Receiver<Arc<ProxyConfig>>,
    whitelist: Arc<Vec<IpNetwork>>,
 ) {
+    let connection_permits = Arc::new(Semaphore::new(METRICS_MAX_CONTROL_CONNECTIONS));
+
    loop {
        let (stream, peer) = match listener.accept().await {
            Ok(v) => v,
@@ -183,17 +204,32 @@ async fn serve_listener(
            continue;
        }

+        let connection_permit = match connection_permits.clone().try_acquire_owned() {
+            Ok(permit) => permit,
+            Err(_) => {
+                debug!(
+                    peer = %peer,
+                    max_connections = METRICS_MAX_CONTROL_CONNECTIONS,
+                    "Dropping metrics connection: control-plane connection budget exhausted"
+                );
+                continue;
+            }
+        };
+
        let stats = stats.clone();
        let beobachten = beobachten.clone();
        let shared_state = shared_state.clone();
        let ip_tracker = ip_tracker.clone();
+        let tls_cache = tls_cache.clone();
        let config_rx_conn = config_rx.clone();
        tokio::spawn(async move {
+            let _connection_permit = connection_permit;
            let svc = service_fn(move |req| {
                let stats = stats.clone();
                let beobachten = beobachten.clone();
                let shared_state = shared_state.clone();
                let ip_tracker = ip_tracker.clone();
+                let tls_cache = tls_cache.clone();
                let config = config_rx_conn.borrow().clone();
                async move {
                    handle(
@@ -202,16 +238,29 @@ async fn serve_listener(
                        &beobachten,
                        &shared_state,
                        &ip_tracker,
+                        tls_cache.as_deref(),
                        &config,
                    )
                    .await
                }
            });
-            if let Err(e) = http1::Builder::new()
-                .serve_connection(hyper_util::rt::TokioIo::new(stream), svc)
-                .await
+            match timeout(
+                METRICS_HTTP_CONNECTION_TIMEOUT,
+                http1::Builder::new().serve_connection(hyper_util::rt::TokioIo::new(stream), svc),
+            )
+            .await
            {
-                debug!(error = %e, "Metrics connection error");
+                Ok(Ok(())) => {}
+                Ok(Err(e)) => {
+                    debug!(error = %e, "Metrics connection error");
+                }
+                Err(_) => {
+                    debug!(
+                        peer = %peer,
+                        timeout_ms = METRICS_HTTP_CONNECTION_TIMEOUT.as_millis() as u64,
+                        "Metrics connection timed out"
+                    );
+                }
            }
        });
    }
@@ -223,10 +272,11 @@ async fn handle<B>(
    beobachten: &BeobachtenStore,
    shared_state: &ProxySharedState,
    ip_tracker: &UserIpTracker,
+    tls_cache: Option<&TlsFrontCache>,
    config: &ProxyConfig,
 ) -> Result<Response<Full<Bytes>>, Infallible> {
    if req.uri().path() == "/metrics" {
-        let body = render_metrics(stats, shared_state, config, ip_tracker).await;
+        let body = render_metrics(stats, shared_state, config, ip_tracker, tls_cache).await;
        let resp = Response::builder()
            .status(StatusCode::OK)
            .header("content-type", "text/plain; version=0.0.4; charset=utf-8")
@@ -261,11 +311,138 @@ fn render_beobachten(beobachten: &BeobachtenStore, config: &ProxyConfig) -> Stri
    beobachten.snapshot_text(ttl)
 }

+fn tls_front_domains(config: &ProxyConfig) -> Vec<String> {
+    let mut domains = Vec::with_capacity(1 + config.censorship.tls_domains.len());
+    if !config.censorship.tls_domain.is_empty() {
+        domains.push(config.censorship.tls_domain.clone());
+    }
+    for domain in &config.censorship.tls_domains {
+        if !domain.is_empty() && !domains.contains(domain) {
+            domains.push(domain.clone());
+        }
+    }
+    domains
+}
+
+fn prometheus_label_value(value: &str) -> String {
+    value.replace('\\', "\\\\").replace('"', "\\\"")
+}
+
+async fn render_tls_front_profile_health(
+    out: &mut String,
+    config: &ProxyConfig,
+    tls_cache: Option<&TlsFrontCache>,
+) {
+    use std::fmt::Write;
+
+    let domains = tls_front_domains(config);
+    let (health, suppressed) = match (config.censorship.tls_emulation, tls_cache) {
+        (true, Some(cache)) => {
+            cache
+                .profile_health_snapshot(&domains, TLS_FRONT_PROFILE_HEALTH_MAX_DOMAINS)
+                .await
+        }
+        _ => (Vec::new(), domains.len()),
+    };
+
+    let _ = writeln!(
+        out,
+        "# HELP telemt_tls_front_profile_domains TLS front configured profile domains by export status"
+    );
+    let _ = writeln!(out, "# TYPE telemt_tls_front_profile_domains gauge");
+    let _ = writeln!(
+        out,
+        "telemt_tls_front_profile_domains{{status=\"configured\"}} {}",
+        domains.len()
+    );
+    let _ = writeln!(
+        out,
+        "telemt_tls_front_profile_domains{{status=\"emitted\"}} {}",
+        health.len()
+    );
+    let _ = writeln!(
+        out,
+        "telemt_tls_front_profile_domains{{status=\"suppressed\"}} {}",
+        suppressed
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_tls_front_profile_info TLS front profile source and feature flags per configured domain"
+    );
+    let _ = writeln!(out, "# TYPE telemt_tls_front_profile_info gauge");
+    let _ = writeln!(
+        out,
+        "# HELP telemt_tls_front_profile_age_seconds Age of cached TLS front profile data per configured domain"
+    );
+    let _ = writeln!(out, "# TYPE telemt_tls_front_profile_age_seconds gauge");
+    let _ = writeln!(
+        out,
+        "# HELP telemt_tls_front_profile_app_data_records TLS front cached app-data record count per configured domain"
+    );
+    let _ = writeln!(
+        out,
+        "# TYPE telemt_tls_front_profile_app_data_records gauge"
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_tls_front_profile_ticket_records TLS front cached ticket-like tail record count per configured domain"
+    );
+    let _ = writeln!(out, "# TYPE telemt_tls_front_profile_ticket_records gauge");
+    let _ = writeln!(
+        out,
+        "# HELP telemt_tls_front_profile_change_cipher_spec_records TLS front cached ChangeCipherSpec record count per configured domain"
+    );
+    let _ = writeln!(
+        out,
+        "# TYPE telemt_tls_front_profile_change_cipher_spec_records gauge"
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_tls_front_profile_app_data_bytes TLS front cached total app-data bytes per configured domain"
+    );
+    let _ = writeln!(out, "# TYPE telemt_tls_front_profile_app_data_bytes gauge");
+
+    for item in health {
+        let domain = prometheus_label_value(&item.domain);
+        let _ = writeln!(
+            out,
+            "telemt_tls_front_profile_info{{domain=\"{}\",source=\"{}\",is_default=\"{}\",has_cert_info=\"{}\",has_cert_payload=\"{}\"}} 1",
+            domain, item.source, item.is_default, item.has_cert_info, item.has_cert_payload
+        );
+        let _ = writeln!(
+            out,
+            "telemt_tls_front_profile_age_seconds{{domain=\"{}\"}} {}",
+            domain, item.age_seconds
+        );
+        let _ = writeln!(
+            out,
+            "telemt_tls_front_profile_app_data_records{{domain=\"{}\"}} {}",
+            domain, item.app_data_records
+        );
+        let _ = writeln!(
+            out,
+            "telemt_tls_front_profile_ticket_records{{domain=\"{}\"}} {}",
+            domain, item.ticket_records
+        );
+        let _ = writeln!(
+            out,
+            "telemt_tls_front_profile_change_cipher_spec_records{{domain=\"{}\"}} {}",
+            domain, item.change_cipher_spec_count
+        );
+        let _ = writeln!(
+            out,
+            "telemt_tls_front_profile_app_data_bytes{{domain=\"{}\"}} {}",
+            domain, item.total_app_data_len
+        );
+    }
+}
+
 async fn render_metrics(
    stats: &Stats,
    shared_state: &ProxySharedState,
    config: &ProxyConfig,
    ip_tracker: &UserIpTracker,
+    tls_cache: Option<&TlsFrontCache>,
 ) -> String {
    use std::fmt::Write;
    let mut out = String::with_capacity(4096);
@@ -311,6 +488,12 @@ async fn render_metrics(
        "telemt_telemetry_user_enabled {}",
        if user_enabled { 1 } else { 0 }
    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_stats_user_entries Retained per-user stats entries"
+    );
+    let _ = writeln!(out, "# TYPE telemt_stats_user_entries gauge");
+    let _ = writeln!(out, "telemt_stats_user_entries {}", stats.user_stats_len());

    let _ = writeln!(
        out,
@@ -366,6 +549,54 @@ async fn render_metrics(
        stats.get_buffer_pool_in_use_gauge()
    );

+    let _ = writeln!(
+        out,
+        "# HELP telemt_tls_fetch_profile_cache_entries Current adaptive TLS fetch profile-cache entries"
+    );
+    let _ = writeln!(out, "# TYPE telemt_tls_fetch_profile_cache_entries gauge");
+    let _ = writeln!(
+        out,
+        "telemt_tls_fetch_profile_cache_entries {}",
+        fetcher::profile_cache_entries_for_metrics()
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_tls_fetch_profile_cache_cap_drops_total Profile-cache winner inserts skipped because the cache cap was reached"
+    );
+    let _ = writeln!(
+        out,
+        "# TYPE telemt_tls_fetch_profile_cache_cap_drops_total counter"
+    );
+    let _ = writeln!(
+        out,
+        "telemt_tls_fetch_profile_cache_cap_drops_total {}",
+        fetcher::profile_cache_cap_drops_for_metrics()
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_tls_front_full_cert_budget_ips Current IP entries tracked by TLS full-cert budget"
+    );
+    let _ = writeln!(out, "# TYPE telemt_tls_front_full_cert_budget_ips gauge");
+    let _ = writeln!(
+        out,
+        "telemt_tls_front_full_cert_budget_ips {}",
+        cache::full_cert_sent_ips_for_metrics()
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_tls_front_full_cert_budget_cap_drops_total New IPs denied full-cert budget tracking because the cap was reached"
+    );
+    let _ = writeln!(
+        out,
+        "# TYPE telemt_tls_front_full_cert_budget_cap_drops_total counter"
+    );
+    let _ = writeln!(
+        out,
+        "telemt_tls_front_full_cert_budget_cap_drops_total {}",
+        cache::full_cert_sent_cap_drops_for_metrics()
+    );
+    render_tls_front_profile_health(&mut out, config, tls_cache).await;
+
    let _ = writeln!(
        out,
        "# HELP telemt_connections_total Total accepted connections"
@@ -396,6 +627,21 @@ async fn render_metrics(
        }
    );

+    let _ = writeln!(
+        out,
+        "# HELP telemt_connections_bad_by_class_total Bad/rejected connections by class"
+    );
+    let _ = writeln!(out, "# TYPE telemt_connections_bad_by_class_total counter");
+    if core_enabled {
+        for (class, total) in stats.get_connects_bad_class_counts() {
+            let _ = writeln!(
+                out,
+                "telemt_connections_bad_by_class_total{{class=\"{}\"}} {}",
+                class, total
+            );
+        }
+    }
+
    let _ = writeln!(
        out,
        "# HELP telemt_handshake_timeouts_total Handshake timeouts"
@@ -411,6 +657,24 @@ async fn render_metrics(
        }
    );

+    let _ = writeln!(
+        out,
+        "# HELP telemt_handshake_failures_by_class_total Handshake failures by class"
+    );
+    let _ = writeln!(
+        out,
+        "# TYPE telemt_handshake_failures_by_class_total counter"
+    );
+    if core_enabled {
+        for (class, total) in stats.get_handshake_failure_class_counts() {
+            let _ = writeln!(
+                out,
+                "telemt_handshake_failures_by_class_total{{class=\"{}\"}} {}",
+                class, total
+            );
+        }
+    }
+
    let _ = writeln!(
        out,
        "# HELP telemt_auth_expensive_checks_total Expensive authentication candidate checks executed during handshake validation"
@@ -462,6 +726,63 @@ async fn render_metrics(
        }
    );

+    let _ = writeln!(
+        out,
+        "# HELP telemt_quota_refund_bytes_total Reserved quota bytes returned before commit"
+    );
+    let _ = writeln!(out, "# TYPE telemt_quota_refund_bytes_total counter");
+    let _ = writeln!(
+        out,
+        "telemt_quota_refund_bytes_total {}",
+        if core_enabled {
+            stats.get_quota_refund_bytes_total()
+        } else {
+            0
+        }
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_quota_contention_total Quota reservation CAS contention events"
+    );
+    let _ = writeln!(out, "# TYPE telemt_quota_contention_total counter");
+    let _ = writeln!(
+        out,
+        "telemt_quota_contention_total {}",
+        if core_enabled {
+            stats.get_quota_contention_total()
+        } else {
+            0
+        }
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_quota_contention_timeout_total Quota reservations that hit the bounded contention budget"
+    );
+    let _ = writeln!(out, "# TYPE telemt_quota_contention_timeout_total counter");
+    let _ = writeln!(
+        out,
+        "telemt_quota_contention_timeout_total {}",
+        if core_enabled {
+            stats.get_quota_contention_timeout_total()
+        } else {
+            0
+        }
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_quota_acquire_cancelled_total Quota acquisitions cancelled before reservation completed"
+    );
+    let _ = writeln!(out, "# TYPE telemt_quota_acquire_cancelled_total counter");
+    let _ = writeln!(
+        out,
+        "telemt_quota_acquire_cancelled_total {}",
+        if core_enabled {
+            stats.get_quota_acquire_cancelled_total()
+        } else {
+            0
+        }
+    );
+
    let _ = writeln!(
        out,
        "# HELP telemt_conntrack_control_state Runtime conntrack control state flags"
@@ -576,6 +897,29 @@ async fn render_metrics(
    );

    let limiter_metrics = shared_state.traffic_limiter.metrics_snapshot();
+    let _ = writeln!(
+        out,
+        "# HELP telemt_rate_limiter_burst_bound_bytes Configured upper bound for one direct relay rate-limit burst"
+    );
+    let _ = writeln!(out, "# TYPE telemt_rate_limiter_burst_bound_bytes gauge");
+    let _ = writeln!(
+        out,
+        "telemt_rate_limiter_burst_bound_bytes{{direction=\"up\"}} {}",
+        if core_enabled {
+            config.general.direct_relay_copy_buf_c2s_bytes
+        } else {
+            0
+        }
+    );
+    let _ = writeln!(
+        out,
+        "telemt_rate_limiter_burst_bound_bytes{{direction=\"down\"}} {}",
+        if core_enabled {
+            config.general.direct_relay_copy_buf_s2c_bytes
+        } else {
+            0
+        }
+    );
    let _ = writeln!(
        out,
        "# HELP telemt_rate_limiter_throttle_total Traffic limiter throttle events by scope and direction"
@@ -1678,6 +2022,85 @@ async fn render_metrics(
            0
        }
    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_me_child_join_timeout_total Middle relay child tasks that did not join before cleanup deadline"
+    );
+    let _ = writeln!(out, "# TYPE telemt_me_child_join_timeout_total counter");
+    let _ = writeln!(
+        out,
+        "telemt_me_child_join_timeout_total {}",
+        if core_enabled {
+            stats.get_me_child_join_timeout_total()
+        } else {
+            0
+        }
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_me_child_abort_total Middle relay child tasks aborted after bounded cleanup timeout"
+    );
+    let _ = writeln!(out, "# TYPE telemt_me_child_abort_total counter");
+    let _ = writeln!(
+        out,
+        "telemt_me_child_abort_total {}",
+        if core_enabled {
+            stats.get_me_child_abort_total()
+        } else {
+            0
+        }
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_flow_wait_events_total Flow wait events by reason, direction, and outcome"
+    );
+    let _ = writeln!(out, "# TYPE telemt_flow_wait_events_total counter");
+    let _ = writeln!(
+        out,
+        "telemt_flow_wait_events_total{{reason=\"middle_rate_limit\",direction=\"down\",outcome=\"waited\"}} {}",
+        if core_enabled {
+            stats.get_flow_wait_middle_rate_limit_total()
+        } else {
+            0
+        }
+    );
+    let _ = writeln!(
+        out,
+        "telemt_flow_wait_events_total{{reason=\"middle_rate_limit\",direction=\"down\",outcome=\"cancelled\"}} {}",
+        if core_enabled {
+            stats.get_flow_wait_middle_rate_limit_cancelled_total()
+        } else {
+            0
+        }
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_flow_wait_ms_total Flow wait time in milliseconds by reason and direction"
+    );
+    let _ = writeln!(out, "# TYPE telemt_flow_wait_ms_total counter");
+    let _ = writeln!(
+        out,
+        "telemt_flow_wait_ms_total{{reason=\"middle_rate_limit\",direction=\"down\"}} {}",
+        if core_enabled {
+            stats.get_flow_wait_middle_rate_limit_ms_total()
+        } else {
+            0
+        }
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_session_drop_fallback_total Session reservations cleaned by Drop instead of explicit async release"
+    );
+    let _ = writeln!(out, "# TYPE telemt_session_drop_fallback_total counter");
+    let _ = writeln!(
+        out,
+        "telemt_session_drop_fallback_total {}",
+        if core_enabled {
+            stats.get_session_drop_fallback_total()
+        } else {
+            0
+        }
+    );

    let _ = writeln!(
        out,
@@ -3019,17 +3442,6 @@ async fn render_metrics(
            0
        }
    );
-    let _ = writeln!(
-        out,
-        "# HELP telemt_telemetry_user_series_suppressed User-labeled metric series suppression flag"
-    );
-    let _ = writeln!(out, "# TYPE telemt_telemetry_user_series_suppressed gauge");
-    let _ = writeln!(
-        out,
-        "telemt_telemetry_user_series_suppressed {}",
-        if user_enabled { 0 } else { 1 }
-    );
-
    let ip_memory = ip_tracker.memory_stats().await;
    let _ = writeln!(
        out,
@@ -3071,11 +3483,46 @@ async fn render_metrics(
        "telemt_ip_tracker_cleanup_queue_len {}",
        ip_memory.cleanup_queue_len
    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_ip_tracker_cleanup_total Release cleanups deferred through the cleanup queue"
+    );
+    let _ = writeln!(out, "# TYPE telemt_ip_tracker_cleanup_total counter");
+    let _ = writeln!(
+        out,
+        "telemt_ip_tracker_cleanup_total{{path=\"deferred\"}} {}",
+        ip_memory.cleanup_deferred_releases
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_ip_tracker_cap_rejects_total New connection rejects caused by global IP tracker caps"
+    );
+    let _ = writeln!(out, "# TYPE telemt_ip_tracker_cap_rejects_total counter");
+    let _ = writeln!(
+        out,
+        "telemt_ip_tracker_cap_rejects_total{{scope=\"active\"}} {}",
+        ip_memory.active_cap_rejects
+    );
+    let _ = writeln!(
+        out,
+        "telemt_ip_tracker_cap_rejects_total{{scope=\"recent\"}} {}",
+        ip_memory.recent_cap_rejects
+    );
+
+    let mut user_stats_emitted = 0usize;
+    let mut user_stats_suppressed = 0usize;
+    let mut unique_ip_emitted = 0usize;
+    let mut unique_ip_suppressed = 0usize;

    if user_enabled {
        for entry in stats.iter_user_stats() {
+            if user_stats_emitted >= USER_LABELED_METRICS_MAX_USERS {
+                user_stats_suppressed = user_stats_suppressed.saturating_add(1);
+                continue;
+            }
            let user = entry.key();
            let s = entry.value();
+            user_stats_emitted = user_stats_emitted.saturating_add(1);
            let _ = writeln!(
                out,
                "telemt_user_connections_total{{user=\"{}\"}} {}",
@@ -3117,7 +3564,7 @@ async fn render_metrics(
            );
        }

-        let ip_stats = ip_tracker.get_stats().await;
+        let ip_stats = ip_tracker.get_stats_snapshot().await;
        let ip_counts: HashMap<String, usize> = ip_stats
            .into_iter()
            .map(|(user, count, _)| (user, count))
@@ -3129,7 +3576,7 @@ async fn render_metrics(
        unique_users.extend(ip_counts.keys().cloned());
        let unique_users_vec: Vec<String> = unique_users.iter().cloned().collect();
        let recent_counts = ip_tracker
-            .get_recent_counts_for_users(&unique_users_vec)
+            .get_recent_counts_for_users_snapshot(&unique_users_vec)
            .await;

        let _ = writeln!(
@@ -3154,6 +3601,11 @@ async fn render_metrics(
        let _ = writeln!(out, "# TYPE telemt_user_unique_ips_utilization gauge");

        for user in unique_users {
+            if unique_ip_emitted >= USER_LABELED_METRICS_MAX_USERS {
+                unique_ip_suppressed = unique_ip_suppressed.saturating_add(1);
+                continue;
+            }
+            unique_ip_emitted = unique_ip_emitted.saturating_add(1);
            let current = ip_counts.get(&user).copied().unwrap_or(0);
            let limit = config
                .access
@@ -3193,6 +3645,46 @@ async fn render_metrics(
        }
    }

+    let _ = writeln!(
+        out,
+        "# HELP telemt_telemetry_user_series_suppressed User-labeled metric series suppression flag"
+    );
+    let _ = writeln!(out, "# TYPE telemt_telemetry_user_series_suppressed gauge");
+    let _ = writeln!(
+        out,
+        "telemt_telemetry_user_series_suppressed {}",
+        if user_enabled && user_stats_suppressed == 0 && unique_ip_suppressed == 0 {
+            0
+        } else {
+            1
+        }
+    );
+    let _ = writeln!(
+        out,
+        "# HELP telemt_telemetry_user_series_users User-labeled metric users by export status"
+    );
+    let _ = writeln!(out, "# TYPE telemt_telemetry_user_series_users gauge");
+    let _ = writeln!(
+        out,
+        "telemt_telemetry_user_series_users{{family=\"stats\",status=\"emitted\"}} {}",
+        user_stats_emitted
+    );
+    let _ = writeln!(
+        out,
+        "telemt_telemetry_user_series_users{{family=\"stats\",status=\"suppressed\"}} {}",
+        user_stats_suppressed
+    );
+    let _ = writeln!(
+        out,
+        "telemt_telemetry_user_series_users{{family=\"unique_ip\",status=\"emitted\"}} {}",
+        unique_ip_emitted
+    );
+    let _ = writeln!(
+        out,
+        "telemt_telemetry_user_series_users{{family=\"unique_ip\",status=\"suppressed\"}} {}",
+        unique_ip_suppressed
+    );
+
    out
 }

@@ -3201,6 +3693,11 @@ mod tests {
    use super::*;
    use http_body_util::BodyExt;
    use std::net::IpAddr;
+    use std::time::SystemTime;
+
+    use crate::tls_front::types::{
+        CachedTlsData, ParsedServerHello, TlsBehaviorProfile, TlsCertPayload, TlsProfileSource,
+    };

    #[tokio::test]
    async fn test_render_metrics_format() {
@@ -3215,8 +3712,9 @@ mod tests {

        stats.increment_connects_all();
        stats.increment_connects_all();
-        stats.increment_connects_bad();
+        stats.increment_connects_bad_with_class("tls_handshake_bad_client");
        stats.increment_handshake_timeouts();
+        stats.increment_handshake_failure_class("timeout");
        shared_state
            .handshake
            .auth_expensive_checks_total
@@ -3268,7 +3766,7 @@ mod tests {
            .await
            .unwrap();

-        let output = render_metrics(&stats, shared_state.as_ref(), &config, &tracker).await;
+        let output = render_metrics(&stats, shared_state.as_ref(), &config, &tracker, None).await;

        assert!(output.contains(&format!(
            "telemt_build_info{{version=\"{}\"}} 1",
@@ -3276,7 +3774,11 @@ mod tests {
        )));
        assert!(output.contains("telemt_connections_total 2"));
        assert!(output.contains("telemt_connections_bad_total 1"));
+        assert!(output.contains(
+            "telemt_connections_bad_by_class_total{class=\"tls_handshake_bad_client\"} 1"
+        ));
        assert!(output.contains("telemt_handshake_timeouts_total 1"));
+        assert!(output.contains("telemt_handshake_failures_by_class_total{class=\"timeout\"} 1"));
        assert!(output.contains("telemt_auth_expensive_checks_total 9"));
        assert!(output.contains("telemt_auth_budget_exhausted_total 2"));
        assert!(output.contains("telemt_upstream_connect_attempt_total 2"));
@@ -3330,13 +3832,91 @@ mod tests {
        assert!(output.contains("telemt_ip_tracker_cleanup_queue_len 0"));
    }

+    #[tokio::test]
+    async fn test_render_tls_front_profile_health() {
+        let stats = Stats::new();
+        let shared_state = ProxySharedState::new();
+        let tracker = UserIpTracker::new();
+        let mut config = ProxyConfig::default();
+        config.censorship.tls_domain = "primary.example".to_string();
+        config.censorship.tls_domains = vec!["fallback.example".to_string()];
+
+        let cache = TlsFrontCache::new(
+            &[
+                "primary.example".to_string(),
+                "fallback.example".to_string(),
+            ],
+            1024,
+            "tlsfront-profile-health-test",
+        );
+        cache
+            .set(
+                "primary.example",
+                CachedTlsData {
+                    server_hello_template: ParsedServerHello {
+                        version: [0x03, 0x03],
+                        random: [0u8; 32],
+                        session_id: Vec::new(),
+                        cipher_suite: [0x13, 0x01],
+                        compression: 0,
+                        extensions: Vec::new(),
+                    },
+                    cert_info: None,
+                    cert_payload: Some(TlsCertPayload {
+                        cert_chain_der: vec![vec![0x30, 0x01]],
+                        certificate_message: vec![0x0b, 0x00, 0x00, 0x00],
+                    }),
+                    app_data_records_sizes: vec![1024, 512],
+                    total_app_data_len: 1536,
+                    behavior_profile: TlsBehaviorProfile {
+                        change_cipher_spec_count: 1,
+                        app_data_record_sizes: vec![1024, 512],
+                        ticket_record_sizes: vec![69],
+                        source: TlsProfileSource::Merged,
+                    },
+                    fetched_at: SystemTime::now(),
+                    domain: "primary.example".to_string(),
+                },
+            )
+            .await;
+
+        let output = render_metrics(&stats, &shared_state, &config, &tracker, Some(&cache)).await;
+
+        assert!(output.contains("telemt_tls_front_profile_domains{status=\"configured\"} 2"));
+        assert!(output.contains("telemt_tls_front_profile_domains{status=\"emitted\"} 2"));
+        assert!(output.contains("telemt_tls_front_profile_domains{status=\"suppressed\"} 0"));
+        assert!(
+            output.contains("telemt_tls_front_profile_info{domain=\"primary.example\",source=\"merged\",is_default=\"false\",has_cert_info=\"false\",has_cert_payload=\"true\"} 1")
+        );
+        assert!(
+            output.contains("telemt_tls_front_profile_info{domain=\"fallback.example\",source=\"default\",is_default=\"true\",has_cert_info=\"false\",has_cert_payload=\"false\"} 1")
+        );
+        assert!(
+            output.contains(
+                "telemt_tls_front_profile_app_data_records{domain=\"primary.example\"} 2"
+            )
+        );
+        assert!(
+            output
+                .contains("telemt_tls_front_profile_ticket_records{domain=\"primary.example\"} 1")
+        );
+        assert!(output.contains(
+            "telemt_tls_front_profile_change_cipher_spec_records{domain=\"primary.example\"} 1"
+        ));
+        assert!(
+            output.contains(
+                "telemt_tls_front_profile_app_data_bytes{domain=\"primary.example\"} 1536"
+            )
+        );
+    }
+
    #[tokio::test]
    async fn test_render_empty_stats() {
        let stats = Stats::new();
        let shared_state = ProxySharedState::new();
        let tracker = UserIpTracker::new();
        let config = ProxyConfig::default();
-        let output = render_metrics(&stats, &shared_state, &config, &tracker).await;
+        let output = render_metrics(&stats, &shared_state, &config, &tracker, None).await;
        assert!(output.contains("telemt_connections_total 0"));
        assert!(output.contains("telemt_connections_bad_total 0"));
        assert!(output.contains("telemt_handshake_timeouts_total 0"));
@@ -3360,7 +3940,7 @@ mod tests {
        let mut config = ProxyConfig::default();
        config.access.user_max_unique_ips_global_each = 2;

-        let output = render_metrics(&stats, &shared_state, &config, &tracker).await;
+        let output = render_metrics(&stats, &shared_state, &config, &tracker, None).await;

        assert!(output.contains("telemt_user_unique_ips_limit{user=\"alice\"} 2"));
        assert!(output.contains("telemt_user_unique_ips_utilization{user=\"alice\"} 0.500000"));
@@ -3372,11 +3952,13 @@ mod tests {
        let shared_state = ProxySharedState::new();
        let tracker = UserIpTracker::new();
        let config = ProxyConfig::default();
-        let output = render_metrics(&stats, &shared_state, &config, &tracker).await;
+        let output = render_metrics(&stats, &shared_state, &config, &tracker, None).await;
        assert!(output.contains("# TYPE telemt_uptime_seconds gauge"));
        assert!(output.contains("# TYPE telemt_connections_total counter"));
        assert!(output.contains("# TYPE telemt_connections_bad_total counter"));
+        assert!(output.contains("# TYPE telemt_connections_bad_by_class_total counter"));
        assert!(output.contains("# TYPE telemt_handshake_timeouts_total counter"));
+        assert!(output.contains("# TYPE telemt_handshake_failures_by_class_total counter"));
        assert!(output.contains("# TYPE telemt_auth_expensive_checks_total counter"));
        assert!(output.contains("# TYPE telemt_auth_budget_exhausted_total counter"));
        assert!(output.contains("# TYPE telemt_upstream_connect_attempt_total counter"));
@@ -3406,9 +3988,28 @@ mod tests {
        assert!(output.contains("# TYPE telemt_user_unique_ips_recent_window gauge"));
        assert!(output.contains("# TYPE telemt_user_unique_ips_limit gauge"));
        assert!(output.contains("# TYPE telemt_user_unique_ips_utilization gauge"));
+        assert!(output.contains("# TYPE telemt_stats_user_entries gauge"));
+        assert!(output.contains("# TYPE telemt_telemetry_user_series_users gauge"));
        assert!(output.contains("# TYPE telemt_ip_tracker_users gauge"));
        assert!(output.contains("# TYPE telemt_ip_tracker_entries gauge"));
        assert!(output.contains("# TYPE telemt_ip_tracker_cleanup_queue_len gauge"));
+        assert!(output.contains("# TYPE telemt_ip_tracker_cleanup_total counter"));
+        assert!(output.contains("# TYPE telemt_ip_tracker_cap_rejects_total counter"));
+        assert!(output.contains("# TYPE telemt_tls_fetch_profile_cache_entries gauge"));
+        assert!(output.contains("# TYPE telemt_tls_fetch_profile_cache_cap_drops_total counter"));
+        assert!(output.contains("# TYPE telemt_tls_front_full_cert_budget_ips gauge"));
+        assert!(
+            output.contains("# TYPE telemt_tls_front_full_cert_budget_cap_drops_total counter")
+        );
+        assert!(output.contains("# TYPE telemt_tls_front_profile_domains gauge"));
+        assert!(output.contains("# TYPE telemt_tls_front_profile_info gauge"));
+        assert!(output.contains("# TYPE telemt_tls_front_profile_age_seconds gauge"));
+        assert!(output.contains("# TYPE telemt_tls_front_profile_app_data_records gauge"));
+        assert!(output.contains("# TYPE telemt_tls_front_profile_ticket_records gauge"));
+        assert!(
+            output.contains("# TYPE telemt_tls_front_profile_change_cipher_spec_records gauge")
+        );
+        assert!(output.contains("# TYPE telemt_tls_front_profile_app_data_bytes gauge"));
    }

    #[tokio::test]
@@ -3429,6 +4030,7 @@ mod tests {
            &beobachten,
            shared_state.as_ref(),
            &tracker,
+            None,
            &config,
        )
        .await
@@ -3463,6 +4065,7 @@ mod tests {
            &beobachten,
            shared_state.as_ref(),
            &tracker,
+            None,
            &config,
        )
        .await
@@ -3480,6 +4083,7 @@ mod tests {
            &beobachten,
            shared_state.as_ref(),
            &tracker,
+            None,
            &config,
        )
        .await
--- a/src/proxy/client.rs
+++ b/src/proxy/client.rs
@@ -31,38 +31,63 @@ struct UserConnectionReservation {
    ip_tracker: Arc<UserIpTracker>,
    user: String,
    ip: IpAddr,
-    active: bool,
+    tracks_ip: bool,
+    state: SessionReservationState,
+}
+
+#[derive(Clone, Copy, PartialEq, Eq)]
+enum SessionReservationState {
+    Active,
+    Released,
 }

 impl UserConnectionReservation {
-    fn new(stats: Arc<Stats>, ip_tracker: Arc<UserIpTracker>, user: String, ip: IpAddr) -> Self {
+    fn new(
+        stats: Arc<Stats>,
+        ip_tracker: Arc<UserIpTracker>,
+        user: String,
+        ip: IpAddr,
+        tracks_ip: bool,
+    ) -> Self {
        Self {
            stats,
            ip_tracker,
            user,
            ip,
-            active: true,
+            tracks_ip,
+            state: SessionReservationState::Active,
        }
    }

+    fn mark_released(&mut self) -> bool {
+        if self.state != SessionReservationState::Active {
+            return false;
+        }
+        self.state = SessionReservationState::Released;
+        true
+    }
+
    async fn release(mut self) {
-        if !self.active {
+        if !self.mark_released() {
            return;
        }
-        self.ip_tracker.remove_ip(&self.user, self.ip).await;
-        self.active = false;
+        if self.tracks_ip {
+            self.ip_tracker.remove_ip(&self.user, self.ip).await;
+        }
        self.stats.decrement_user_curr_connects(&self.user);
    }
 }

 impl Drop for UserConnectionReservation {
    fn drop(&mut self) {
-        if !self.active {
+        if !self.mark_released() {
            return;
        }
-        self.active = false;
+        self.stats.increment_session_drop_fallback_total();
        self.stats.decrement_user_curr_connects(&self.user);
-        self.ip_tracker.enqueue_cleanup(self.user.clone(), self.ip);
+        if self.tracks_ip {
+            self.ip_tracker.enqueue_cleanup(self.user.clone(), self.ip);
+        }
    }
 }

@@ -454,6 +479,17 @@ where
    let mut local_addr = synthetic_local_addr(config.server.port);

    if proxy_protocol_enabled {
+        if !is_trusted_proxy_source(peer.ip(), &config.server.proxy_protocol_trusted_cidrs) {
+            stats.increment_connects_bad_with_class("proxy_protocol_untrusted");
+            warn!(
+                peer = %peer,
+                trusted = ?config.server.proxy_protocol_trusted_cidrs,
+                "Rejecting PROXY protocol header from untrusted source"
+            );
+            record_beobachten_class(&beobachten, &config, peer.ip(), "other");
+            return Err(ProxyError::InvalidProxyProtocol);
+        }
+
        let proxy_header_timeout =
            Duration::from_millis(config.server.proxy_protocol_header_timeout_ms.max(1));
        match timeout(
@@ -463,17 +499,6 @@ where
        .await
        {
            Ok(Ok(info)) => {
-                if !is_trusted_proxy_source(peer.ip(), &config.server.proxy_protocol_trusted_cidrs)
-                {
-                    stats.increment_connects_bad_with_class("proxy_protocol_untrusted");
-                    warn!(
-                        peer = %peer,
-                        trusted = ?config.server.proxy_protocol_trusted_cidrs,
-                        "Rejecting PROXY protocol header from untrusted source"
-                    );
-                    record_beobachten_class(&beobachten, &config, peer.ip(), "other");
-                    return Err(ProxyError::InvalidProxyProtocol);
-                }
                debug!(
                    peer = %peer,
                    client = %info.src_addr,
@@ -966,6 +991,21 @@ impl RunningClientHandler {
        let mut local_addr = self.stream.local_addr().map_err(ProxyError::Io)?;

        if self.proxy_protocol_enabled {
+            if !is_trusted_proxy_source(
+                self.peer.ip(),
+                &self.config.server.proxy_protocol_trusted_cidrs,
+            ) {
+                self.stats
+                    .increment_connects_bad_with_class("proxy_protocol_untrusted");
+                warn!(
+                    peer = %self.peer,
+                    trusted = ?self.config.server.proxy_protocol_trusted_cidrs,
+                    "Rejecting PROXY protocol header from untrusted source"
+                );
+                record_beobachten_class(&self.beobachten, &self.config, self.peer.ip(), "other");
+                return Err(ProxyError::InvalidProxyProtocol);
+            }
+
            let proxy_header_timeout =
                Duration::from_millis(self.config.server.proxy_protocol_header_timeout_ms.max(1));
            match timeout(
@@ -975,25 +1015,6 @@ impl RunningClientHandler {
            .await
            {
                Ok(Ok(info)) => {
-                    if !is_trusted_proxy_source(
-                        self.peer.ip(),
-                        &self.config.server.proxy_protocol_trusted_cidrs,
-                    ) {
-                        self.stats
-                            .increment_connects_bad_with_class("proxy_protocol_untrusted");
-                        warn!(
-                            peer = %self.peer,
-                            trusted = ?self.config.server.proxy_protocol_trusted_cidrs,
-                            "Rejecting PROXY protocol header from untrusted source"
-                        );
-                        record_beobachten_class(
-                            &self.beobachten,
-                            &self.config,
-                            self.peer.ip(),
-                            "other",
-                        );
-                        return Err(ProxyError::InvalidProxyProtocol);
-                    }
                    debug!(
                        peer = %self.peer,
                        client = %info.src_addr,
@@ -1419,8 +1440,8 @@ impl RunningClientHandler {

    /// Main dispatch after successful handshake.
    /// Two modes:
-    ///   - Direct: TCP relay to TG DC (existing behavior)  
-    ///   - Middle Proxy: RPC multiplex through ME pool (new — supports CDN DCs)
+    ///   - Direct: TCP relay to TG DC (existing behavior)
+    ///   - Middle Proxy: RPC multiplex through ME pool (supports CDN DCs)
    #[cfg(test)]
    async fn handle_authenticated_static<R, W>(
        client_reader: CryptoReader<R>,
@@ -1621,6 +1642,7 @@ impl RunningClientHandler {
            ip_tracker,
            user.to_string(),
            peer_addr.ip(),
+            true,
        ))
    }

@@ -1666,7 +1688,6 @@ impl RunningClientHandler {
        match ip_tracker.check_and_add(user, peer_addr.ip()).await {
            Ok(()) => {
                ip_tracker.remove_ip(user, peer_addr.ip()).await;
-                stats.decrement_user_curr_connects(user);
            }
            Err(reason) => {
                stats.decrement_user_curr_connects(user);
@@ -1682,6 +1703,7 @@ impl RunningClientHandler {
            }
        }

+        stats.decrement_user_curr_connects(user);
        Ok(())
    }
 }
--- a/src/proxy/direct_relay.rs
+++ b/src/proxy/direct_relay.rs
@@ -18,8 +18,7 @@ use crate::error::{ProxyError, Result};
 use crate::protocol::constants::*;
 use crate::proxy::handshake::{HandshakeSuccess, encrypt_tg_nonce_with_ciphers, generate_tg_nonce};
 use crate::proxy::route_mode::{
-    ROUTE_SWITCH_ERROR_MSG, RelayRouteMode, RouteCutoverState, affected_cutover_state,
-    cutover_stagger_delay,
+    RelayRouteMode, RouteCutoverState, affected_cutover_state, cutover_stagger_delay,
 };
 use crate::proxy::shared_state::{
    ConntrackCloseEvent, ConntrackClosePublishResult, ConntrackCloseReason, ProxySharedState,
@@ -360,7 +359,7 @@ where
                "Cutover affected direct session, closing client connection"
            );
            tokio::time::sleep(delay).await;
-            break Err(ProxyError::Proxy(ROUTE_SWITCH_ERROR_MSG.to_string()));
+            break Err(ProxyError::RouteSwitched);
        }
        tokio::select! {
            result = &mut relay_result => {
--- a/src/proxy/handshake.rs
+++ b/src/proxy/handshake.rs
@@ -55,6 +55,7 @@ const STICKY_HINT_MAX_ENTRIES: usize = 65_536;
 const CANDIDATE_HINT_TRACK_CAP: usize = 64;
 const OVERLOAD_CANDIDATE_BUDGET_HINTED: usize = 16;
 const OVERLOAD_CANDIDATE_BUDGET_UNHINTED: usize = 8;
+const EXPENSIVE_INVALID_SCAN_SATURATION_THRESHOLD: usize = 64;
 const RECENT_USER_RING_SCAN_LIMIT: usize = 32;

 type HmacSha256 = Hmac<Sha256>;
@@ -551,6 +552,19 @@ fn auth_probe_note_saturation_in(shared: &ProxySharedState, now: Instant) {
    }
 }

+fn auth_probe_note_expensive_invalid_scan_in(
+    shared: &ProxySharedState,
+    now: Instant,
+    validation_checks: usize,
+    overload: bool,
+) {
+    if overload || validation_checks < EXPENSIVE_INVALID_SCAN_SATURATION_THRESHOLD {
+        return;
+    }
+
+    auth_probe_note_saturation_in(shared, now);
+}
+
 fn auth_probe_record_failure_in(shared: &ProxySharedState, peer_ip: IpAddr, now: Instant) {
    let peer_ip = normalize_auth_probe_ip(peer_ip);
    let state = &shared.handshake.auth_probe;
@@ -1378,7 +1392,14 @@ where
        }

        if !matched {
-            auth_probe_record_failure_in(shared, peer.ip(), Instant::now());
+            let failure_now = Instant::now();
+            auth_probe_note_expensive_invalid_scan_in(
+                shared,
+                failure_now,
+                validation_checks,
+                overload,
+            );
+            auth_probe_record_failure_in(shared, peer.ip(), failure_now);
            maybe_apply_server_hello_delay(config).await;
            debug!(
                peer = %peer,
@@ -1429,6 +1450,20 @@ where
        validated_secret.copy_from_slice(secret);
    }

+    if config
+        .access
+        .is_user_source_ip_denied(validated_user.as_str(), peer.ip())
+    {
+        auth_probe_record_failure_in(shared, peer.ip(), Instant::now());
+        maybe_apply_server_hello_delay(config).await;
+        warn!(
+            peer = %peer,
+            user = %validated_user,
+            "TLS handshake rejected: client source IP on per-user deny list (access.user_source_deny)"
+        );
+        return HandshakeResult::BadClient { reader, writer };
+    }
+
    // Reject known replay digests before expensive cache/domain/ALPN policy work.
    let digest_half = &validation_digest[..tls::TLS_DIGEST_HALF_LEN];
    if replay_checker.check_tls_digest(digest_half) {
@@ -1753,7 +1788,14 @@ where
        }

        if !matched {
-            auth_probe_record_failure_in(shared, peer.ip(), Instant::now());
+            let failure_now = Instant::now();
+            auth_probe_note_expensive_invalid_scan_in(
+                shared,
+                failure_now,
+                validation_checks,
+                overload,
+            );
+            auth_probe_record_failure_in(shared, peer.ip(), failure_now);
            maybe_apply_server_hello_delay(config).await;
            debug!(
                peer = %peer,
@@ -1767,6 +1809,20 @@ where

        let validation = matched_validation.expect("validation must exist when matched");

+        if config
+            .access
+            .is_user_source_ip_denied(matched_user.as_str(), peer.ip())
+        {
+            auth_probe_record_failure_in(shared, peer.ip(), Instant::now());
+            maybe_apply_server_hello_delay(config).await;
+            warn!(
+                peer = %peer,
+                user = %matched_user,
+                "MTProto handshake rejected: client source IP on per-user deny list (access.user_source_deny)"
+            );
+            return HandshakeResult::BadClient { reader, writer };
+        }
+
        // Apply replay tracking only after successful authentication.
        //
        // This ordering prevents an attacker from producing invalid handshakes that
@@ -1845,6 +1901,20 @@ where
                .auth_expensive_checks_total
                .fetch_add(validation_checks as u64, Ordering::Relaxed);

+            if config
+                .access
+                .is_user_source_ip_denied(user.as_str(), peer.ip())
+            {
+                auth_probe_record_failure_in(shared, peer.ip(), Instant::now());
+                maybe_apply_server_hello_delay(config).await;
+                warn!(
+                    peer = %peer,
+                    user = %user,
+                    "MTProto handshake rejected: client source IP on per-user deny list (access.user_source_deny)"
+                );
+                return HandshakeResult::BadClient { reader, writer };
+            }
+
            // Apply replay tracking only after successful authentication.
            //
            // This ordering prevents an attacker from producing invalid handshakes that
--- a/src/proxy/masking.rs
+++ b/src/proxy/masking.rs
@@ -2,6 +2,7 @@

 use crate::config::ProxyConfig;
 use crate::network::dns_overrides::resolve_socket_addr;
+use crate::protocol::tls;
 use crate::stats::beobachten::BeobachtenStore;
 use crate::transport::proxy_protocol::{ProxyProtocolV1Builder, ProxyProtocolV2Builder};
 #[cfg(unix)]
@@ -328,6 +329,89 @@ async fn wait_mask_outcome_budget(started: Instant, config: &ProxyConfig) {
    }
 }

+#[cfg(test)]
+mod tls_domain_mask_host_tests {
+    use super::{mask_host_for_initial_data, matching_tls_domain_for_sni};
+    use crate::config::ProxyConfig;
+
+    fn client_hello_with_sni(sni_host: &str) -> Vec<u8> {
+        let mut body = Vec::new();
+        body.extend_from_slice(&[0x03, 0x03]);
+        body.extend_from_slice(&[0u8; 32]);
+        body.push(32);
+        body.extend_from_slice(&[0x42u8; 32]);
+        body.extend_from_slice(&2u16.to_be_bytes());
+        body.extend_from_slice(&[0x13, 0x01]);
+        body.push(1);
+        body.push(0);
+
+        let host_bytes = sni_host.as_bytes();
+        let mut sni_payload = Vec::new();
+        sni_payload.extend_from_slice(&((host_bytes.len() + 3) as u16).to_be_bytes());
+        sni_payload.push(0);
+        sni_payload.extend_from_slice(&(host_bytes.len() as u16).to_be_bytes());
+        sni_payload.extend_from_slice(host_bytes);
+
+        let mut extensions = Vec::new();
+        extensions.extend_from_slice(&0x0000u16.to_be_bytes());
+        extensions.extend_from_slice(&(sni_payload.len() as u16).to_be_bytes());
+        extensions.extend_from_slice(&sni_payload);
+        body.extend_from_slice(&(extensions.len() as u16).to_be_bytes());
+        body.extend_from_slice(&extensions);
+
+        let mut handshake = Vec::new();
+        handshake.push(0x01);
+        let body_len = (body.len() as u32).to_be_bytes();
+        handshake.extend_from_slice(&body_len[1..4]);
+        handshake.extend_from_slice(&body);
+
+        let mut record = Vec::new();
+        record.push(0x16);
+        record.extend_from_slice(&[0x03, 0x01]);
+        record.extend_from_slice(&(handshake.len() as u16).to_be_bytes());
+        record.extend_from_slice(&handshake);
+        record
+    }
+
+    fn config_with_tls_domains() -> ProxyConfig {
+        let mut config = ProxyConfig::default();
+        config.censorship.tls_domain = "a.com".to_string();
+        config.censorship.tls_domains = vec!["b.com".to_string(), "c.com".to_string()];
+        config.censorship.mask_host = Some("a.com".to_string());
+        config
+    }
+
+    #[test]
+    fn matching_tls_domain_accepts_primary_and_extra_domains_case_insensitively() {
+        let config = config_with_tls_domains();
+
+        assert_eq!(matching_tls_domain_for_sni(&config, "A.COM"), Some("a.com"));
+        assert_eq!(matching_tls_domain_for_sni(&config, "B.COM"), Some("b.com"));
+        assert_eq!(matching_tls_domain_for_sni(&config, "unknown.com"), None);
+    }
+
+    #[test]
+    fn mask_host_preserves_explicit_non_primary_origin() {
+        let mut config = config_with_tls_domains();
+        config.censorship.mask_host = Some("origin.example".to_string());
+
+        let initial_data = client_hello_with_sni("b.com");
+
+        assert_eq!(
+            mask_host_for_initial_data(&config, &initial_data),
+            "origin.example"
+        );
+    }
+
+    #[test]
+    fn mask_host_uses_matching_tls_domain_when_mask_host_is_primary_default() {
+        let config = config_with_tls_domains();
+        let initial_data = client_hello_with_sni("b.com");
+
+        assert_eq!(mask_host_for_initial_data(&config, &initial_data), "b.com");
+    }
+}
+
 /// Detect client type based on initial data
 fn detect_client_type(data: &[u8]) -> &'static str {
    // Check for HTTP request
@@ -360,6 +444,37 @@ fn parse_mask_host_ip_literal(host: &str) -> Option<IpAddr> {
    host.parse::<IpAddr>().ok()
 }

+fn matching_tls_domain_for_sni<'a>(config: &'a ProxyConfig, sni: &str) -> Option<&'a str> {
+    if config.censorship.tls_domain.eq_ignore_ascii_case(sni) {
+        return Some(config.censorship.tls_domain.as_str());
+    }
+
+    for domain in &config.censorship.tls_domains {
+        if domain.eq_ignore_ascii_case(sni) {
+            return Some(domain.as_str());
+        }
+    }
+
+    None
+}
+
+fn mask_host_for_initial_data<'a>(config: &'a ProxyConfig, initial_data: &[u8]) -> &'a str {
+    let configured_mask_host = config
+        .censorship
+        .mask_host
+        .as_deref()
+        .unwrap_or(&config.censorship.tls_domain);
+
+    if !configured_mask_host.eq_ignore_ascii_case(&config.censorship.tls_domain) {
+        return configured_mask_host;
+    }
+
+    tls::extract_sni_from_client_hello(initial_data)
+        .as_deref()
+        .and_then(|sni| matching_tls_domain_for_sni(config, sni))
+        .unwrap_or(configured_mask_host)
+}
+
 fn canonical_ip(ip: IpAddr) -> IpAddr {
    match ip {
        IpAddr::V6(v6) => v6
@@ -734,11 +849,7 @@ pub async fn handle_bad_client<R, W>(
        return;
    }

-    let mask_host = config
-        .censorship
-        .mask_host
-        .as_deref()
-        .unwrap_or(&config.censorship.tls_domain);
+    let mask_host = mask_host_for_initial_data(config, initial_data);
    let mask_port = config.censorship.mask_port;

    // Fail closed when fallback points at our own listener endpoint.
--- a/src/proxy/middle_relay.rs
+++ b/src/proxy/middle_relay.rs
@@ -12,8 +12,9 @@ use std::sync::atomic::{AtomicU64, Ordering};
 use std::time::{Duration, Instant};

 use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
-use tokio::sync::{mpsc, oneshot, watch};
+use tokio::sync::{OwnedSemaphorePermit, Semaphore, mpsc, oneshot, watch};
 use tokio::time::timeout;
+use tokio_util::sync::CancellationToken;
 use tracing::{debug, info, trace, warn};

 use crate::config::{ConntrackPressureProfile, ProxyConfig};
@@ -22,8 +23,7 @@ use crate::error::{ProxyError, Result};
 use crate::protocol::constants::{secure_padding_len, *};
 use crate::proxy::handshake::HandshakeSuccess;
 use crate::proxy::route_mode::{
-    ROUTE_SWITCH_ERROR_MSG, RelayRouteMode, RouteCutoverState, affected_cutover_state,
-    cutover_stagger_delay,
+    RelayRouteMode, RouteCutoverState, affected_cutover_state, cutover_stagger_delay,
 };
 use crate::proxy::shared_state::{
    ConntrackCloseEvent, ConntrackClosePublishResult, ConntrackCloseReason, ProxySharedState,
@@ -36,7 +36,11 @@ use crate::stream::{BufferPool, CryptoReader, CryptoWriter, PooledBuffer};
 use crate::transport::middle_proxy::{MePool, MeResponse, proto_flags_for_tag};

 enum C2MeCommand {
-    Data { payload: PooledBuffer, flags: u32 },
+    Data {
+        payload: PooledBuffer,
+        flags: u32,
+        _permit: OwnedSemaphorePermit,
+    },
    Close,
 }

@@ -47,6 +51,8 @@ const DESYNC_ERROR_CLASS: &str = "frame_too_large_crypto_desync";
 const C2ME_CHANNEL_CAPACITY_FALLBACK: usize = 128;
 const C2ME_SOFT_PRESSURE_MIN_FREE_SLOTS: usize = 64;
 const C2ME_SENDER_FAIRNESS_BUDGET: usize = 32;
+const C2ME_QUEUED_BYTE_PERMIT_UNIT: usize = 16 * 1024;
+const C2ME_QUEUED_PERMITS_PER_SLOT: usize = 4;
 const RELAY_IDLE_IO_POLL_MAX: Duration = Duration::from_secs(1);
 const TINY_FRAME_DEBT_PER_TINY: u32 = 8;
 const TINY_FRAME_DEBT_LIMIT: u32 = 512;
@@ -59,6 +65,15 @@ const ME_D2C_SINGLE_WRITE_COALESCE_MAX_BYTES: usize = 128 * 1024;
 const QUOTA_RESERVE_SPIN_RETRIES: usize = 32;
 const QUOTA_RESERVE_BACKOFF_MIN_MS: u64 = 1;
 const QUOTA_RESERVE_BACKOFF_MAX_MS: u64 = 16;
+const QUOTA_RESERVE_MAX_BACKOFF_ROUNDS: usize = 16;
+const ME_CHILD_JOIN_TIMEOUT: Duration = Duration::from_secs(2);
+
+enum MiddleQuotaReserveError {
+    LimitExceeded,
+    Contended,
+    Cancelled,
+    DeadlineExceeded,
+}

 #[derive(Default)]
 pub(crate) struct DesyncDedupRotationState {
@@ -571,6 +586,43 @@ fn should_yield_c2me_sender(sent_since_yield: usize, has_backlog: bool) -> bool
    has_backlog && sent_since_yield >= C2ME_SENDER_FAIRNESS_BUDGET
 }

+fn c2me_payload_permits(payload_len: usize) -> u32 {
+    payload_len
+        .max(1)
+        .div_ceil(C2ME_QUEUED_BYTE_PERMIT_UNIT)
+        .min(u32::MAX as usize) as u32
+}
+
+fn c2me_queued_permit_budget(channel_capacity: usize, frame_limit: usize) -> usize {
+    channel_capacity
+        .saturating_mul(C2ME_QUEUED_PERMITS_PER_SLOT)
+        .max(c2me_payload_permits(frame_limit) as usize)
+        .max(1)
+}
+
+async fn acquire_c2me_payload_permit(
+    semaphore: &Arc<Semaphore>,
+    payload_len: usize,
+    send_timeout: Option<Duration>,
+    stats: &Stats,
+) -> Result<OwnedSemaphorePermit> {
+    let permits = c2me_payload_permits(payload_len);
+    let acquire = semaphore.clone().acquire_many_owned(permits);
+    match send_timeout {
+        Some(send_timeout) => match timeout(send_timeout, acquire).await {
+            Ok(Ok(permit)) => Ok(permit),
+            Ok(Err(_)) => Err(ProxyError::Proxy("ME sender byte budget closed".into())),
+            Err(_) => {
+                stats.increment_me_c2me_send_timeout_total();
+                Err(ProxyError::Proxy("ME sender byte budget timeout".into()))
+            }
+        },
+        None => acquire
+            .await
+            .map_err(|_| ProxyError::Proxy("ME sender byte budget closed".into())),
+    }
+}
+
 fn quota_soft_cap(limit: u64, overshoot: u64) -> u64 {
    limit.saturating_add(overshoot)
 }
@@ -579,21 +631,43 @@ async fn reserve_user_quota_with_yield(
    user_stats: &UserStats,
    bytes: u64,
    limit: u64,
-) -> std::result::Result<u64, QuotaReserveError> {
+    stats: &Stats,
+    cancel: &CancellationToken,
+    deadline: Option<Instant>,
+) -> std::result::Result<u64, MiddleQuotaReserveError> {
    let mut backoff_ms = QUOTA_RESERVE_BACKOFF_MIN_MS;
+    let mut backoff_rounds = 0usize;
    loop {
        for _ in 0..QUOTA_RESERVE_SPIN_RETRIES {
            match user_stats.quota_try_reserve(bytes, limit) {
                Ok(total) => return Ok(total),
                Err(QuotaReserveError::LimitExceeded) => {
-                    return Err(QuotaReserveError::LimitExceeded);
+                    return Err(MiddleQuotaReserveError::LimitExceeded);
+                }
+                Err(QuotaReserveError::Contended) => {
+                    stats.increment_quota_contention_total();
+                    std::hint::spin_loop();
                }
-                Err(QuotaReserveError::Contended) => std::hint::spin_loop(),
            }
        }

        tokio::task::yield_now().await;
-        tokio::time::sleep(Duration::from_millis(backoff_ms)).await;
+        if deadline.is_some_and(|deadline| Instant::now() >= deadline) {
+            stats.increment_quota_contention_timeout_total();
+            return Err(MiddleQuotaReserveError::DeadlineExceeded);
+        }
+        tokio::select! {
+            _ = tokio::time::sleep(Duration::from_millis(backoff_ms)) => {}
+            _ = cancel.cancelled() => {
+                stats.increment_quota_acquire_cancelled_total();
+                return Err(MiddleQuotaReserveError::Cancelled);
+            }
+        }
+        backoff_rounds = backoff_rounds.saturating_add(1);
+        if backoff_rounds >= QUOTA_RESERVE_MAX_BACKOFF_ROUNDS {
+            stats.increment_quota_contention_timeout_total();
+            return Err(MiddleQuotaReserveError::Contended);
+        }
        backoff_ms = backoff_ms
            .saturating_mul(2)
            .min(QUOTA_RESERVE_BACKOFF_MAX_MS);
@@ -604,12 +678,13 @@ async fn wait_for_traffic_budget(
    lease: Option<&Arc<TrafficLease>>,
    direction: RateDirection,
    bytes: u64,
-) {
+    deadline: Option<Instant>,
+) -> Result<()> {
    if bytes == 0 {
-        return;
+        return Ok(());
    }
    let Some(lease) = lease else {
-        return;
+        return Ok(());
    };

    let mut remaining = bytes;
@@ -621,6 +696,9 @@ async fn wait_for_traffic_budget(
        }

        let wait_started_at = Instant::now();
+        if deadline.is_some_and(|deadline| wait_started_at >= deadline) {
+            return Err(ProxyError::TrafficBudgetWaitDeadlineExceeded);
+        }
        tokio::time::sleep(next_refill_delay()).await;
        let wait_ms = wait_started_at
            .elapsed()
@@ -633,6 +711,59 @@ async fn wait_for_traffic_budget(
            wait_ms,
        );
    }
+
+    Ok(())
+}
+
+async fn wait_for_traffic_budget_or_cancel(
+    lease: Option<&Arc<TrafficLease>>,
+    direction: RateDirection,
+    bytes: u64,
+    cancel: &CancellationToken,
+    stats: &Stats,
+    deadline: Option<Instant>,
+) -> Result<()> {
+    if bytes == 0 {
+        return Ok(());
+    }
+    let Some(lease) = lease else {
+        return Ok(());
+    };
+
+    let mut remaining = bytes;
+    while remaining > 0 {
+        let consume = lease.try_consume(direction, remaining);
+        if consume.granted > 0 {
+            remaining = remaining.saturating_sub(consume.granted);
+            continue;
+        }
+
+        let wait_started_at = Instant::now();
+        if deadline.is_some_and(|deadline| wait_started_at >= deadline) {
+            stats.increment_flow_wait_middle_rate_limit_cancelled_total();
+            return Err(ProxyError::TrafficBudgetWaitDeadlineExceeded);
+        }
+        tokio::select! {
+            _ = tokio::time::sleep(next_refill_delay()) => {}
+            _ = cancel.cancelled() => {
+                stats.increment_flow_wait_middle_rate_limit_cancelled_total();
+                return Err(ProxyError::TrafficBudgetWaitCancelled);
+            }
+        }
+        let wait_ms = wait_started_at
+            .elapsed()
+            .as_millis()
+            .min(u128::from(u64::MAX)) as u64;
+        lease.observe_wait_ms(
+            direction,
+            consume.blocked_user,
+            consume.blocked_cidr,
+            wait_ms,
+        );
+        stats.observe_flow_wait_middle_rate_limit_ms(wait_ms);
+    }
+
+    Ok(())
 }

 fn classify_me_d2c_flush_reason(
@@ -1071,7 +1202,7 @@ where
        tokio::time::sleep(delay).await;
        let _ = me_pool.send_close(conn_id).await;
        me_pool.registry().unregister(conn_id).await;
-        return Err(ProxyError::Proxy(ROUTE_SWITCH_ERROR_MSG.to_string()));
+        return Err(ProxyError::RouteSwitched);
    }

    // Per-user ad_tag from access.user_ad_tags; fallback to general.ad_tag (hot-reloadable)
@@ -1122,13 +1253,19 @@ where
        0 => None,
        timeout_ms => Some(Duration::from_millis(timeout_ms)),
    };
+    let c2me_byte_budget = c2me_queued_permit_budget(c2me_channel_capacity, frame_limit);
+    let c2me_byte_semaphore = Arc::new(Semaphore::new(c2me_byte_budget));
    let (c2me_tx, mut c2me_rx) = mpsc::channel::<C2MeCommand>(c2me_channel_capacity);
    let me_pool_c2me = me_pool.clone();
-    let c2me_sender = tokio::spawn(async move {
+    let mut c2me_sender = tokio::spawn(async move {
        let mut sent_since_yield = 0usize;
        while let Some(cmd) = c2me_rx.recv().await {
            match cmd {
-                C2MeCommand::Data { payload, flags } => {
+                C2MeCommand::Data {
+                    payload,
+                    flags,
+                    _permit,
+                } => {
                    me_pool_c2me
                        .send_proxy_req(
                            conn_id,
@@ -1156,16 +1293,18 @@ where
    });

    let (stop_tx, mut stop_rx) = oneshot::channel::<()>();
+    let flow_cancel = CancellationToken::new();
    let mut me_rx_task = me_rx;
    let stats_clone = stats.clone();
    let rng_clone = rng.clone();
    let user_clone = user.clone();
    let quota_user_stats_me_writer = quota_user_stats.clone();
    let traffic_lease_me_writer = traffic_lease.clone();
+    let flow_cancel_me_writer = flow_cancel.clone();
    let last_downstream_activity_ms_clone = last_downstream_activity_ms.clone();
    let bytes_me2c_clone = bytes_me2c.clone();
    let d2c_flush_policy = MeD2cFlushPolicy::from_config(&config);
-    let me_writer = tokio::spawn(async move {
+    let mut me_writer = tokio::spawn(async move {
        let mut writer = crypto_writer;
        let mut frame_buf = Vec::with_capacity(16 * 1024);
        let shrink_threshold = d2c_flush_policy.frame_buf_shrink_threshold_bytes;
@@ -1185,7 +1324,7 @@ where
                    let Some(first) = msg else {
                        debug!(conn_id, "ME channel closed");
                        shrink_session_vec(&mut frame_buf, shrink_threshold);
-                        return Err(ProxyError::Proxy("ME connection lost".into()));
+                        return Err(ProxyError::MiddleConnectionLost);
                    };

                    let mut batch_frames = 0usize;
@@ -1207,6 +1346,7 @@ where
                        quota_limit,
                        d2c_flush_policy.quota_soft_overshoot_bytes,
                        traffic_lease_me_writer.as_ref(),
+                        &flow_cancel_me_writer,
                        bytes_me2c_clone.as_ref(),
                        conn_id,
                        d2c_flush_policy.ack_flush_immediate,
@@ -1227,7 +1367,7 @@ where
                            } else {
                                None
                            };
-                            let _ = writer.flush().await;
+                            let _ = flush_client_or_cancel(&mut writer, &flow_cancel_me_writer).await;
                            let flush_duration_us = flush_started_at.map(|started| {
                                started
                                    .elapsed()
@@ -1268,6 +1408,7 @@ where
                            quota_limit,
                            d2c_flush_policy.quota_soft_overshoot_bytes,
                            traffic_lease_me_writer.as_ref(),
+                            &flow_cancel_me_writer,
                            bytes_me2c_clone.as_ref(),
                            conn_id,
                            d2c_flush_policy.ack_flush_immediate,
@@ -1289,7 +1430,8 @@ where
                                    } else {
                                        None
                                    };
-                                let _ = writer.flush().await;
+                                let _ =
+                                    flush_client_or_cancel(&mut writer, &flow_cancel_me_writer).await;
                                let flush_duration_us = flush_started_at.map(|started| {
                                    started
                                        .elapsed()
@@ -1332,6 +1474,7 @@ where
                                    quota_limit,
                                    d2c_flush_policy.quota_soft_overshoot_bytes,
                                    traffic_lease_me_writer.as_ref(),
+                                    &flow_cancel_me_writer,
                                    bytes_me2c_clone.as_ref(),
                                    conn_id,
                                    d2c_flush_policy.ack_flush_immediate,
@@ -1356,7 +1499,11 @@ where
                                        } else {
                                            None
                                        };
-                                        let _ = writer.flush().await;
+                                        let _ = flush_client_or_cancel(
+                                            &mut writer,
+                                            &flow_cancel_me_writer,
+                                        )
+                                        .await;
                                        let flush_duration_us = flush_started_at.map(|started| {
                                            started
                                                .elapsed()
@@ -1398,6 +1545,7 @@ where
                                        quota_limit,
                                        d2c_flush_policy.quota_soft_overshoot_bytes,
                                        traffic_lease_me_writer.as_ref(),
+                                        &flow_cancel_me_writer,
                                        bytes_me2c_clone.as_ref(),
                                        conn_id,
                                        d2c_flush_policy.ack_flush_immediate,
@@ -1422,7 +1570,11 @@ where
                                            } else {
                                                None
                                            };
-                                            let _ = writer.flush().await;
+                                            let _ = flush_client_or_cancel(
+                                                &mut writer,
+                                                &flow_cancel_me_writer,
+                                            )
+                                            .await;
                                            let flush_duration_us = flush_started_at.map(|started| {
                                                started
                                                    .elapsed()
@@ -1446,7 +1598,7 @@ where
                            Ok(None) => {
                                debug!(conn_id, "ME channel closed");
                                shrink_session_vec(&mut frame_buf, shrink_threshold);
-                                return Err(ProxyError::Proxy("ME connection lost".into()));
+                                return Err(ProxyError::MiddleConnectionLost);
                            }
                            Err(_) => {
                                max_delay_fired = true;
@@ -1468,7 +1620,7 @@ where
                    } else {
                        None
                    };
-                    writer.flush().await.map_err(ProxyError::Io)?;
+                    flush_client_or_cancel(&mut writer, &flow_cancel_me_writer).await?;
                    let flush_duration_us = flush_started_at.map(|started| {
                        started
                            .elapsed()
@@ -1561,7 +1713,7 @@ where
                stats.as_ref(),
            )
            .await;
-            main_result = Err(ProxyError::Proxy(ROUTE_SWITCH_ERROR_MSG.to_string()));
+            main_result = Err(ProxyError::RouteSwitched);
            break;
        }

@@ -1592,26 +1744,50 @@ where
                            traffic_lease.as_ref(),
                            RateDirection::Up,
                            payload.len() as u64,
+                            None,
                        )
-                        .await;
+                        .await?;
                        forensics.bytes_c2me = forensics
                            .bytes_c2me
                            .saturating_add(payload.len() as u64);
                        if let (Some(limit), Some(user_stats)) =
                            (quota_limit, quota_user_stats.as_deref())
                        {
-                            if reserve_user_quota_with_yield(
+                            match reserve_user_quota_with_yield(
                                user_stats,
                                payload.len() as u64,
                                limit,
+                                stats.as_ref(),
+                                &flow_cancel,
+                                None,
                            )
                            .await
-                            .is_err()
                            {
-                                main_result = Err(ProxyError::DataQuotaExceeded {
-                                    user: user.clone(),
-                                });
-                                break;
+                                Ok(_) => {}
+                                Err(MiddleQuotaReserveError::LimitExceeded) => {
+                                    main_result = Err(ProxyError::DataQuotaExceeded {
+                                        user: user.clone(),
+                                    });
+                                    break;
+                                }
+                                Err(MiddleQuotaReserveError::Contended) => {
+                                    main_result = Err(ProxyError::Proxy(
+                                        "ME C->ME quota reservation contended".into(),
+                                    ));
+                                    break;
+                                }
+                                Err(MiddleQuotaReserveError::Cancelled) => {
+                                    main_result = Err(ProxyError::Proxy(
+                                        "ME C->ME quota reservation cancelled".into(),
+                                    ));
+                                    break;
+                                }
+                                Err(MiddleQuotaReserveError::DeadlineExceeded) => {
+                                    main_result = Err(ProxyError::Proxy(
+                                        "ME C->ME quota reservation deadline exceeded".into(),
+                                    ));
+                                    break;
+                                }
                            }
                            stats.add_user_octets_from_handle(user_stats, payload.len() as u64);
                        } else {
@@ -1624,11 +1800,29 @@ where
                        if payload.len() >= 8 && payload[..8].iter().all(|b| *b == 0) {
                            flags |= RPC_FLAG_NOT_ENCRYPTED;
                        }
+                        let payload_permit = match acquire_c2me_payload_permit(
+                            &c2me_byte_semaphore,
+                            payload.len(),
+                            c2me_send_timeout,
+                            stats.as_ref(),
+                        )
+                        .await
+                        {
+                            Ok(permit) => permit,
+                            Err(e) => {
+                                main_result = Err(e);
+                                break;
+                            }
+                        };
                        // Keep client read loop lightweight: route heavy ME send path via a dedicated task.
                        if enqueue_c2me_command_in(
                            shared.as_ref(),
                            &c2me_tx,
-                            C2MeCommand::Data { payload, flags },
+                            C2MeCommand::Data {
+                                payload,
+                                flags,
+                                _permit: payload_permit,
+                            },
                            c2me_send_timeout,
                            stats.as_ref(),
                        )
@@ -1662,22 +1856,34 @@ where
    }

    drop(c2me_tx);
-    let c2me_result = c2me_sender
-        .await
-        .unwrap_or_else(|e| Err(ProxyError::Proxy(format!("ME sender join error: {e}"))));
+    let c2me_result = match timeout(ME_CHILD_JOIN_TIMEOUT, &mut c2me_sender).await {
+        Ok(joined) => {
+            joined.unwrap_or_else(|e| Err(ProxyError::Proxy(format!("ME sender join error: {e}"))))
+        }
+        Err(_) => {
+            stats.increment_me_child_join_timeout_total();
+            stats.increment_me_child_abort_total();
+            c2me_sender.abort();
+            Err(ProxyError::Proxy("ME sender join timeout".into()))
+        }
+    };

+    flow_cancel.cancel();
    let _ = stop_tx.send(());
-    let mut writer_result = me_writer
-        .await
-        .unwrap_or_else(|e| Err(ProxyError::Proxy(format!("ME writer join error: {e}"))));
+    let mut writer_result = match timeout(ME_CHILD_JOIN_TIMEOUT, &mut me_writer).await {
+        Ok(joined) => {
+            joined.unwrap_or_else(|e| Err(ProxyError::Proxy(format!("ME writer join error: {e}"))))
+        }
+        Err(_) => {
+            stats.increment_me_child_join_timeout_total();
+            stats.increment_me_child_abort_total();
+            me_writer.abort();
+            Err(ProxyError::Proxy("ME writer join timeout".into()))
+        }
+    };

    // When client closes, but ME channel stopped as unregistered - it isnt error
-    if client_closed
-        && matches!(
-            writer_result,
-            Err(ProxyError::Proxy(ref msg)) if msg == "ME connection lost"
-        )
-    {
+    if client_closed && matches!(writer_result, Err(ProxyError::MiddleConnectionLost)) {
        writer_result = Ok(());
    }

@@ -2233,6 +2439,7 @@ where
        quota_limit,
        quota_soft_overshoot_bytes,
        None,
+        &CancellationToken::new(),
        bytes_me2c,
        conn_id,
        ack_flush_immediate,
@@ -2253,6 +2460,7 @@ async fn process_me_writer_response_with_traffic_lease<W>(
    quota_limit: Option<u64>,
    quota_soft_overshoot_bytes: u64,
    traffic_lease: Option<&Arc<TrafficLease>>,
+    cancel: &CancellationToken,
    bytes_me2c: &AtomicU64,
    conn_id: u64,
    ack_flush_immediate: bool,
@@ -2262,7 +2470,7 @@ where
    W: AsyncWrite + Unpin + Send + 'static,
 {
    match response {
-        MeResponse::Data { flags, data } => {
+        MeResponse::Data { flags, data, .. } => {
            if batched {
                trace!(conn_id, bytes = data.len(), flags, "ME->C data (batched)");
            } else {
@@ -2271,31 +2479,65 @@ where
            let data_len = data.len() as u64;
            if let (Some(limit), Some(user_stats)) = (quota_limit, quota_user_stats) {
                let soft_limit = quota_soft_cap(limit, quota_soft_overshoot_bytes);
-                if reserve_user_quota_with_yield(user_stats, data_len, soft_limit)
-                    .await
-                    .is_err()
+                match reserve_user_quota_with_yield(
+                    user_stats, data_len, soft_limit, stats, cancel, None,
+                )
+                .await
                {
-                    stats.increment_me_d2c_quota_reject_total(MeD2cQuotaRejectStage::PreWrite);
-                    return Err(ProxyError::DataQuotaExceeded {
-                        user: user.to_string(),
-                    });
+                    Ok(_) => {}
+                    Err(MiddleQuotaReserveError::LimitExceeded) => {
+                        stats.increment_me_d2c_quota_reject_total(MeD2cQuotaRejectStage::PreWrite);
+                        return Err(ProxyError::DataQuotaExceeded {
+                            user: user.to_string(),
+                        });
+                    }
+                    Err(MiddleQuotaReserveError::Contended) => {
+                        return Err(ProxyError::Proxy(
+                            "ME D->C quota reservation contended".into(),
+                        ));
+                    }
+                    Err(MiddleQuotaReserveError::Cancelled) => {
+                        return Err(ProxyError::Proxy(
+                            "ME D->C quota reservation cancelled".into(),
+                        ));
+                    }
+                    Err(MiddleQuotaReserveError::DeadlineExceeded) => {
+                        return Err(ProxyError::Proxy(
+                            "ME D->C quota reservation deadline exceeded".into(),
+                        ));
+                    }
                }
            }
-            wait_for_traffic_budget(traffic_lease, RateDirection::Down, data_len).await;
+            wait_for_traffic_budget_or_cancel(
+                traffic_lease,
+                RateDirection::Down,
+                data_len,
+                cancel,
+                stats,
+                None,
+            )
+            .await?;

-            let write_mode =
-                match write_client_payload(client_writer, proto_tag, flags, &data, rng, frame_buf)
-                    .await
-                {
-                    Ok(mode) => mode,
-                    Err(err) => {
-                        if quota_limit.is_some() {
-                            stats.add_quota_write_fail_bytes_total(data_len);
-                            stats.increment_quota_write_fail_events_total();
-                        }
-                        return Err(err);
+            let write_mode = match write_client_payload(
+                client_writer,
+                proto_tag,
+                flags,
+                &data,
+                rng,
+                frame_buf,
+                cancel,
+            )
+            .await
+            {
+                Ok(mode) => mode,
+                Err(err) => {
+                    if quota_limit.is_some() {
+                        stats.add_quota_write_fail_bytes_total(data_len);
+                        stats.increment_quota_write_fail_events_total();
                    }
-                };
+                    return Err(err);
+                }
+            };

            bytes_me2c.fetch_add(data_len, Ordering::Relaxed);
            if let Some(user_stats) = quota_user_stats {
@@ -2319,8 +2561,16 @@ where
            } else {
                trace!(conn_id, confirm, "ME->C quickack");
            }
-            wait_for_traffic_budget(traffic_lease, RateDirection::Down, 4).await;
-            write_client_ack(client_writer, proto_tag, confirm).await?;
+            wait_for_traffic_budget_or_cancel(
+                traffic_lease,
+                RateDirection::Down,
+                4,
+                cancel,
+                stats,
+                None,
+            )
+            .await?;
+            write_client_ack(client_writer, proto_tag, confirm, cancel).await?;
            stats.increment_me_d2c_ack_frames_total();

            Ok(MeWriterResponseOutcome::Continue {
@@ -2372,6 +2622,7 @@ async fn write_client_payload<W>(
    data: &[u8],
    rng: &SecureRandom,
    frame_buf: &mut Vec<u8>,
+    cancel: &CancellationToken,
 ) -> Result<MeD2cWriteMode>
 where
    W: AsyncWrite + Unpin + Send + 'static,
@@ -2399,21 +2650,12 @@ where
                    frame_buf.reserve(wire_len);
                    frame_buf.push(first);
                    frame_buf.extend_from_slice(data);
-                    client_writer
-                        .write_all(frame_buf.as_slice())
-                        .await
-                        .map_err(ProxyError::Io)?;
+                    write_all_client_or_cancel(client_writer, frame_buf.as_slice(), cancel).await?;
                    MeD2cWriteMode::Coalesced
                } else {
                    let header = [first];
-                    client_writer
-                        .write_all(&header)
-                        .await
-                        .map_err(ProxyError::Io)?;
-                    client_writer
-                        .write_all(data)
-                        .await
-                        .map_err(ProxyError::Io)?;
+                    write_all_client_or_cancel(client_writer, &header, cancel).await?;
+                    write_all_client_or_cancel(client_writer, data, cancel).await?;
                    MeD2cWriteMode::Split
                }
            } else if len_words < (1 << 24) {
@@ -2428,21 +2670,12 @@ where
                    frame_buf.reserve(wire_len);
                    frame_buf.extend_from_slice(&[first, lw[0], lw[1], lw[2]]);
                    frame_buf.extend_from_slice(data);
-                    client_writer
-                        .write_all(frame_buf.as_slice())
-                        .await
-                        .map_err(ProxyError::Io)?;
+                    write_all_client_or_cancel(client_writer, frame_buf.as_slice(), cancel).await?;
                    MeD2cWriteMode::Coalesced
                } else {
                    let header = [first, lw[0], lw[1], lw[2]];
-                    client_writer
-                        .write_all(&header)
-                        .await
-                        .map_err(ProxyError::Io)?;
-                    client_writer
-                        .write_all(data)
-                        .await
-                        .map_err(ProxyError::Io)?;
+                    write_all_client_or_cancel(client_writer, &header, cancel).await?;
+                    write_all_client_or_cancel(client_writer, data, cancel).await?;
                    MeD2cWriteMode::Split
                }
            } else {
@@ -2477,21 +2710,12 @@ where
                    frame_buf.resize(start + padding_len, 0);
                    rng.fill(&mut frame_buf[start..]);
                }
-                client_writer
-                    .write_all(frame_buf.as_slice())
-                    .await
-                    .map_err(ProxyError::Io)?;
+                write_all_client_or_cancel(client_writer, frame_buf.as_slice(), cancel).await?;
                MeD2cWriteMode::Coalesced
            } else {
                let header = len_val.to_le_bytes();
-                client_writer
-                    .write_all(&header)
-                    .await
-                    .map_err(ProxyError::Io)?;
-                client_writer
-                    .write_all(data)
-                    .await
-                    .map_err(ProxyError::Io)?;
+                write_all_client_or_cancel(client_writer, &header, cancel).await?;
+                write_all_client_or_cancel(client_writer, data, cancel).await?;
                if padding_len > 0 {
                    frame_buf.clear();
                    if frame_buf.capacity() < padding_len {
@@ -2499,10 +2723,7 @@ where
                    }
                    frame_buf.resize(padding_len, 0);
                    rng.fill(frame_buf.as_mut_slice());
-                    client_writer
-                        .write_all(frame_buf.as_slice())
-                        .await
-                        .map_err(ProxyError::Io)?;
+                    write_all_client_or_cancel(client_writer, frame_buf.as_slice(), cancel).await?;
                }
                MeD2cWriteMode::Split
            }
@@ -2516,6 +2737,7 @@ async fn write_client_ack<W>(
    client_writer: &mut CryptoWriter<W>,
    proto_tag: ProtoTag,
    confirm: u32,
+    cancel: &CancellationToken,
 ) -> Result<()>
 where
    W: AsyncWrite + Unpin + Send + 'static,
@@ -2525,10 +2747,34 @@ where
    } else {
        confirm.to_le_bytes()
    };
-    client_writer
-        .write_all(&bytes)
-        .await
-        .map_err(ProxyError::Io)
+    write_all_client_or_cancel(client_writer, &bytes, cancel).await
+}
+
+async fn write_all_client_or_cancel<W>(
+    client_writer: &mut CryptoWriter<W>,
+    bytes: &[u8],
+    cancel: &CancellationToken,
+) -> Result<()>
+where
+    W: AsyncWrite + Unpin + Send + 'static,
+{
+    tokio::select! {
+        result = client_writer.write_all(bytes) => result.map_err(ProxyError::Io),
+        _ = cancel.cancelled() => Err(ProxyError::MiddleClientWriterCancelled),
+    }
+}
+
+async fn flush_client_or_cancel<W>(
+    client_writer: &mut CryptoWriter<W>,
+    cancel: &CancellationToken,
+) -> Result<()>
+where
+    W: AsyncWrite + Unpin + Send + 'static,
+{
+    tokio::select! {
+        result = client_writer.flush() => result.map_err(ProxyError::Io),
+        _ = cancel.cancelled() => Err(ProxyError::MiddleClientWriterCancelled),
+    }
 }

 #[cfg(test)]
--- a/src/proxy/relay.rs
+++ b/src/proxy/relay.rs
@@ -215,6 +215,7 @@ struct StatsIo<S> {
    c2s_rate_debt_bytes: u64,
    c2s_wait: RateWaitState,
    s2c_wait: RateWaitState,
+    quota_wait: RateWaitState,
    quota_limit: Option<u64>,
    quota_exceeded: Arc<AtomicBool>,
    quota_bytes_since_check: u64,
@@ -275,6 +276,7 @@ impl<S> StatsIo<S> {
            c2s_rate_debt_bytes: 0,
            c2s_wait: RateWaitState::default(),
            s2c_wait: RateWaitState::default(),
+            quota_wait: RateWaitState::default(),
            quota_limit,
            quota_exceeded,
            quota_bytes_since_check: 0,
@@ -353,6 +355,11 @@ impl<S> StatsIo<S> {

        Poll::Ready(())
    }
+
+    fn arm_quota_wait(&mut self, cx: &mut Context<'_>) -> Poll<()> {
+        Self::arm_wait(&mut self.quota_wait, false, false);
+        Self::poll_wait(&mut self.quota_wait, cx, None, RateDirection::Up)
+    }
 }

 #[derive(Debug)]
@@ -430,8 +437,13 @@ impl<S: AsyncRead + Unpin> AsyncRead for StatsIo<S> {
        if this.settle_c2s_rate_debt(cx).is_pending() {
            return Poll::Pending;
        }
+        if buf.remaining() == 0 {
+            return Pin::new(&mut this.inner).poll_read(cx, buf);
+        }

        let mut remaining_before = None;
+        let mut reserved_read_bytes = 0u64;
+        let mut read_limit = buf.remaining();
        if let Some(limit) = this.quota_limit {
            let used_before = this.user_stats.quota_used();
            let remaining = limit.saturating_sub(used_before);
@@ -440,50 +452,79 @@ impl<S: AsyncRead + Unpin> AsyncRead for StatsIo<S> {
                return Poll::Ready(Err(quota_io_error()));
            }
            remaining_before = Some(remaining);
+            read_limit = read_limit.min(remaining as usize);
+            if read_limit == 0 {
+                this.quota_exceeded.store(true, Ordering::Release);
+                return Poll::Ready(Err(quota_io_error()));
+            }
+
+            let desired = read_limit as u64;
+            let mut reserve_rounds = 0usize;
+            while reserved_read_bytes == 0 {
+                for _ in 0..QUOTA_RESERVE_SPIN_RETRIES {
+                    match this.user_stats.quota_try_reserve(desired, limit) {
+                        Ok(_) => {
+                            reserved_read_bytes = desired;
+                            break;
+                        }
+                        Err(crate::stats::QuotaReserveError::LimitExceeded) => {
+                            this.quota_exceeded.store(true, Ordering::Release);
+                            return Poll::Ready(Err(quota_io_error()));
+                        }
+                        Err(crate::stats::QuotaReserveError::Contended) => {
+                            this.stats.increment_quota_contention_total();
+                        }
+                    }
+                }
+
+                if reserved_read_bytes == 0 {
+                    reserve_rounds = reserve_rounds.saturating_add(1);
+                    if reserve_rounds >= QUOTA_RESERVE_MAX_ROUNDS {
+                        this.stats.increment_quota_contention_timeout_total();
+                        if this.arm_quota_wait(cx).is_pending() {
+                            return Poll::Pending;
+                        }
+                        reserve_rounds = 0;
+                    }
+                }
+            }
        }

-        let before = buf.filled().len();
+        let limited_read = read_limit < buf.remaining();
+        let read_result = if limited_read {
+            let mut limited_buf = ReadBuf::new(buf.initialize_unfilled_to(read_limit));
+            match Pin::new(&mut this.inner).poll_read(cx, &mut limited_buf) {
+                Poll::Ready(Ok(())) => {
+                    let n = limited_buf.filled().len();
+                    buf.advance(n);
+                    Poll::Ready(Ok(n))
+                }
+                Poll::Ready(Err(err)) => Poll::Ready(Err(err)),
+                Poll::Pending => Poll::Pending,
+            }
+        } else {
+            let before = buf.filled().len();
+            match Pin::new(&mut this.inner).poll_read(cx, buf) {
+                Poll::Ready(Ok(())) => {
+                    let n = buf.filled().len() - before;
+                    Poll::Ready(Ok(n))
+                }
+                Poll::Ready(Err(err)) => Poll::Ready(Err(err)),
+                Poll::Pending => Poll::Pending,
+            }
+        };

-        match Pin::new(&mut this.inner).poll_read(cx, buf) {
-            Poll::Ready(Ok(())) => {
-                let n = buf.filled().len() - before;
+        match read_result {
+            Poll::Ready(Ok(n)) => {
+                if reserved_read_bytes > n as u64 {
+                    let refund_bytes = reserved_read_bytes - n as u64;
+                    refund_reserved_quota_bytes(this.user_stats.as_ref(), refund_bytes);
+                    this.stats.add_quota_refund_bytes_total(refund_bytes);
+                }
                if n > 0 {
                    let n_to_charge = n as u64;

-                    if let (Some(limit), Some(remaining)) = (this.quota_limit, remaining_before) {
-                        let mut reserved_total = None;
-                        let mut reserve_rounds = 0usize;
-                        while reserved_total.is_none() {
-                            let mut saw_contention = false;
-                            for _ in 0..QUOTA_RESERVE_SPIN_RETRIES {
-                                match this.user_stats.quota_try_reserve(n_to_charge, limit) {
-                                    Ok(total) => {
-                                        reserved_total = Some(total);
-                                        break;
-                                    }
-                                    Err(crate::stats::QuotaReserveError::LimitExceeded) => {
-                                        this.quota_exceeded.store(true, Ordering::Release);
-                                        buf.set_filled(before);
-                                        return Poll::Ready(Err(quota_io_error()));
-                                    }
-                                    Err(crate::stats::QuotaReserveError::Contended) => {
-                                        saw_contention = true;
-                                    }
-                                }
-                            }
-                            if reserved_total.is_none() {
-                                reserve_rounds = reserve_rounds.saturating_add(1);
-                                if reserve_rounds >= QUOTA_RESERVE_MAX_ROUNDS {
-                                    this.quota_exceeded.store(true, Ordering::Release);
-                                    buf.set_filled(before);
-                                    return Poll::Ready(Err(quota_io_error()));
-                                }
-                                if saw_contention {
-                                    std::thread::yield_now();
-                                }
-                            }
-                        }
-
+                    if let Some(remaining) = remaining_before {
                        if should_immediate_quota_check(remaining, n_to_charge) {
                            this.quota_bytes_since_check = 0;
                        } else {
@@ -494,10 +535,11 @@ impl<S: AsyncRead + Unpin> AsyncRead for StatsIo<S> {
                                this.quota_bytes_since_check = 0;
                            }
                        }
-
-                        if reserved_total.unwrap_or(0) >= limit {
-                            this.quota_exceeded.store(true, Ordering::Release);
-                        }
+                    }
+                    if let Some(limit) = this.quota_limit
+                        && this.user_stats.quota_used() >= limit
+                    {
+                        this.quota_exceeded.store(true, Ordering::Release);
                    }

                    // C→S: client sent data
@@ -521,7 +563,20 @@ impl<S: AsyncRead + Unpin> AsyncRead for StatsIo<S> {
                }
                Poll::Ready(Ok(()))
            }
-            other => other,
+            Poll::Pending => {
+                if reserved_read_bytes > 0 {
+                    refund_reserved_quota_bytes(this.user_stats.as_ref(), reserved_read_bytes);
+                    this.stats.add_quota_refund_bytes_total(reserved_read_bytes);
+                }
+                Poll::Pending
+            }
+            Poll::Ready(Err(err)) => {
+                if reserved_read_bytes > 0 {
+                    refund_reserved_quota_bytes(this.user_stats.as_ref(), reserved_read_bytes);
+                    this.stats.add_quota_refund_bytes_total(reserved_read_bytes);
+                }
+                Poll::Ready(Err(err))
+            }
        }
    }
 }
@@ -603,6 +658,7 @@ impl<S: AsyncWrite + Unpin> AsyncWrite for StatsIo<S> {
                                break;
                            }
                            Err(crate::stats::QuotaReserveError::Contended) => {
+                                this.stats.increment_quota_contention_total();
                                saw_contention = true;
                            }
                        }
@@ -611,14 +667,14 @@ impl<S: AsyncWrite + Unpin> AsyncWrite for StatsIo<S> {
                    if reserved_bytes == 0 {
                        reserve_rounds = reserve_rounds.saturating_add(1);
                        if reserve_rounds >= QUOTA_RESERVE_MAX_ROUNDS {
+                            this.stats.increment_quota_contention_timeout_total();
                            if let Some(lease) = this.traffic_lease.as_ref() {
                                lease.refund(RateDirection::Down, shaper_reserved_bytes);
                            }
-                            this.quota_exceeded.store(true, Ordering::Release);
-                            return Poll::Ready(Err(quota_io_error()));
-                        }
-                        if saw_contention {
-                            std::thread::yield_now();
+                            let _ = this.arm_quota_wait(cx);
+                            return Poll::Pending;
+                        } else if saw_contention {
+                            std::hint::spin_loop();
                        }
                    }
                }
@@ -639,10 +695,9 @@ impl<S: AsyncWrite + Unpin> AsyncWrite for StatsIo<S> {
        match Pin::new(&mut this.inner).poll_write(cx, write_buf) {
            Poll::Ready(Ok(n)) => {
                if reserved_bytes > n as u64 {
-                    refund_reserved_quota_bytes(
-                        this.user_stats.as_ref(),
-                        reserved_bytes - n as u64,
-                    );
+                    let refund_bytes = reserved_bytes - n as u64;
+                    refund_reserved_quota_bytes(this.user_stats.as_ref(), refund_bytes);
+                    this.stats.add_quota_refund_bytes_total(refund_bytes);
                }
                if shaper_reserved_bytes > n as u64
                    && let Some(lease) = this.traffic_lease.as_ref()
@@ -693,6 +748,7 @@ impl<S: AsyncWrite + Unpin> AsyncWrite for StatsIo<S> {
            Poll::Ready(Err(err)) => {
                if reserved_bytes > 0 {
                    refund_reserved_quota_bytes(this.user_stats.as_ref(), reserved_bytes);
+                    this.stats.add_quota_refund_bytes_total(reserved_bytes);
                }
                if shaper_reserved_bytes > 0
                    && let Some(lease) = this.traffic_lease.as_ref()
@@ -704,6 +760,7 @@ impl<S: AsyncWrite + Unpin> AsyncWrite for StatsIo<S> {
            Poll::Pending => {
                if reserved_bytes > 0 {
                    refund_reserved_quota_bytes(this.user_stats.as_ref(), reserved_bytes);
+                    this.stats.add_quota_refund_bytes_total(reserved_bytes);
                }
                if shaper_reserved_bytes > 0
                    && let Some(lease) = this.traffic_lease.as_ref()
--- a/src/proxy/route_mode.rs
+++ b/src/proxy/route_mode.rs
@@ -4,8 +4,6 @@ use std::time::{Duration, SystemTime, UNIX_EPOCH};

 use tokio::sync::watch;

-pub(crate) const ROUTE_SWITCH_ERROR_MSG: &str = "Session terminated";
-
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 #[repr(u8)]
 pub(crate) enum RelayRouteMode {
--- a/src/proxy/tests/client_security_tests.rs
+++ b/src/proxy/tests/client_security_tests.rs
@@ -282,7 +282,7 @@ async fn user_connection_reservation_drop_enqueues_cleanup_synchronously() {
    assert_eq!(stats.get_user_curr_connects(&user), 1);

    let reservation =
-        UserConnectionReservation::new(stats.clone(), ip_tracker.clone(), user.clone(), ip);
+        UserConnectionReservation::new(stats.clone(), ip_tracker.clone(), user.clone(), ip, true);

    // Drop the reservation synchronously without any tokio::spawn/await yielding!
    drop(reservation);
@@ -320,6 +320,7 @@ async fn relay_task_abort_releases_user_gate_and_ip_reservation() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, 8).await;

    let mut cfg = ProxyConfig::default();
    cfg.access.user_max_tcp_conns.insert(user.to_string(), 8);
@@ -437,6 +438,7 @@ async fn relay_cutover_releases_user_gate_and_ip_reservation() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, 8).await;

    let mut cfg = ProxyConfig::default();
    cfg.access.user_max_tcp_conns.insert(user.to_string(), 8);
@@ -659,7 +661,7 @@ async fn integration_route_cutover_and_quota_overlap_fails_closed_and_releases_s

    assert!(
        matches!(relay_result, Err(ProxyError::DataQuotaExceeded { .. }))
-            || matches!(relay_result, Err(ProxyError::Proxy(ref msg)) if msg == crate::proxy::route_mode::ROUTE_SWITCH_ERROR_MSG),
+            || matches!(relay_result, Err(ProxyError::RouteSwitched)),
        "overlap race must fail closed via quota enforcement or generic cutover termination"
    );

@@ -958,6 +960,36 @@ async fn reservation_limit_failure_does_not_leak_curr_connects_counter() {
    assert_eq!(ip_tracker.get_active_ip_count(user).await, 0);
 }

+#[tokio::test]
+async fn unlimited_unique_ip_user_is_still_visible_in_active_ip_tracker() {
+    let user = "active-ip-observed-user";
+    let config = crate::config::ProxyConfig::default();
+    let stats = Arc::new(crate::stats::Stats::new());
+    let ip_tracker = Arc::new(crate::ip_tracker::UserIpTracker::new());
+    let peer = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(198, 51, 200, 17)), 50017);
+
+    let reservation = RunningClientHandler::acquire_user_connection_reservation_static(
+        user,
+        &config,
+        stats.clone(),
+        peer,
+        ip_tracker.clone(),
+    )
+    .await
+    .expect("reservation without unique-IP limit must succeed");
+
+    assert_eq!(stats.get_user_curr_connects(user), 1);
+    assert_eq!(
+        ip_tracker.get_active_ip_count(user).await,
+        1,
+        "active IP observability must not depend on unique-IP limit enforcement"
+    );
+
+    reservation.release().await;
+    assert_eq!(stats.get_user_curr_connects(user), 0);
+    assert_eq!(ip_tracker.get_active_ip_count(user).await, 0);
+}
+
 #[tokio::test]
 async fn short_tls_probe_is_masked_through_client_pipeline() {
    let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
@@ -2879,6 +2911,7 @@ async fn explicit_reservation_release_cleans_user_and_ip_immediately() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, 4).await;

    let reservation = RunningClientHandler::acquire_user_connection_reservation_static(
        user,
@@ -2917,6 +2950,7 @@ async fn explicit_reservation_release_does_not_double_decrement_on_drop() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, 4).await;

    let reservation = RunningClientHandler::acquire_user_connection_reservation_static(
        user,
@@ -2947,6 +2981,7 @@ async fn drop_fallback_eventually_cleans_user_and_ip_reservation() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, 1).await;

    let reservation = RunningClientHandler::acquire_user_connection_reservation_static(
        user,
@@ -3029,6 +3064,7 @@ async fn release_abort_storm_does_not_leak_user_or_ip_reservations() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, ATTEMPTS + 16).await;

    for idx in 0..ATTEMPTS {
        let peer = SocketAddr::new(
@@ -3079,6 +3115,7 @@ async fn release_abort_loop_preserves_immediate_same_ip_reacquire() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, 1).await;

    for _ in 0..ITERATIONS {
        let reservation = RunningClientHandler::acquire_user_connection_reservation_static(
@@ -3137,6 +3174,7 @@ async fn adversarial_mixed_release_drop_abort_wave_converges_to_zero() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, RESERVATIONS + 8).await;

    let mut reservations = Vec::with_capacity(RESERVATIONS);
    for idx in 0..RESERVATIONS {
@@ -3217,6 +3255,8 @@ async fn parallel_users_abort_release_isolation_preserves_independent_cleanup()

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user_a, 64).await;
+    ip_tracker.set_user_limit(user_b, 64).await;

    let mut tasks = tokio::task::JoinSet::new();
    for idx in 0..64usize {
@@ -3278,6 +3318,7 @@ async fn concurrent_release_storm_leaves_zero_user_and_ip_footprint() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, RESERVATIONS + 8).await;

    let mut reservations = Vec::with_capacity(RESERVATIONS);
    for idx in 0..RESERVATIONS {
@@ -3332,6 +3373,7 @@ async fn relay_connect_error_releases_user_and_ip_before_return() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, 8).await;

    let mut config = ProxyConfig::default();
    config.access.user_max_tcp_conns.insert(user.to_string(), 1);
@@ -3427,6 +3469,7 @@ async fn mixed_release_and_drop_same_ip_preserves_counter_correctness() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, 1).await;

    let reservation_a = RunningClientHandler::acquire_user_connection_reservation_static(
        user,
@@ -3487,6 +3530,7 @@ async fn drop_one_of_two_same_ip_reservations_keeps_ip_active() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, 1).await;

    let reservation_a = RunningClientHandler::acquire_user_connection_reservation_static(
        user,
@@ -3696,6 +3740,7 @@ async fn cross_thread_drop_uses_captured_runtime_for_ip_cleanup() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, 8).await;

    let reservation = RunningClientHandler::acquire_user_connection_reservation_static(
        user,
@@ -3740,6 +3785,7 @@ async fn immediate_reacquire_after_cross_thread_drop_succeeds() {

    let stats = Arc::new(Stats::new());
    let ip_tracker = Arc::new(UserIpTracker::new());
+    ip_tracker.set_user_limit(user, 1).await;

    let reservation = RunningClientHandler::acquire_user_connection_reservation_static(
        user,
--- a/src/proxy/tests/direct_relay_security_tests.rs
+++ b/src/proxy/tests/direct_relay_security_tests.rs
@@ -637,6 +637,22 @@ fn unknown_dc_log_path_revalidation_rejects_parent_swapped_to_symlink() {
            "telemt-unknown-dc-parent-swap-{}",
            std::process::id()
        ));
+    if let Ok(meta) = fs::symlink_metadata(&parent) {
+        if meta.file_type().is_symlink() || meta.is_file() {
+            fs::remove_file(&parent).expect("stale parent-swap path must be removable");
+        } else {
+            fs::remove_dir_all(&parent).expect("stale parent-swap directory must be removable");
+        }
+    }
+    let moved = parent.with_extension("bak");
+    if let Ok(meta) = fs::symlink_metadata(&moved) {
+        if meta.file_type().is_symlink() || meta.is_file() {
+            fs::remove_file(&moved).expect("stale parent-swap backup path must be removable");
+        } else {
+            fs::remove_dir_all(&moved)
+                .expect("stale parent-swap backup directory must be removable");
+        }
+    }
    fs::create_dir_all(&parent).expect("parent-swap test parent must be creatable");

    let rel_candidate = format!(
@@ -646,8 +662,6 @@ fn unknown_dc_log_path_revalidation_rejects_parent_swapped_to_symlink() {
    let sanitized = sanitize_unknown_dc_log_path(&rel_candidate)
        .expect("candidate must sanitize before parent swap");

-    let moved = parent.with_extension("bak");
-    let _ = fs::remove_dir_all(&moved);
    fs::rename(&parent, &moved).expect("parent must be movable for swap simulation");
    symlink("/tmp", &parent).expect("symlink replacement for parent must be creatable");

@@ -669,6 +683,13 @@ fn adversarial_check_then_symlink_flip_is_blocked_by_nofollow_open() {
            "telemt-unknown-dc-check-open-race-{}",
            std::process::id()
        ));
+    if let Ok(meta) = fs::symlink_metadata(&parent) {
+        if meta.file_type().is_symlink() || meta.is_file() {
+            fs::remove_file(&parent).expect("stale check-open-race path must be removable");
+        } else {
+            fs::remove_dir_all(&parent).expect("stale check-open-race parent must be removable");
+        }
+    }
    fs::create_dir_all(&parent).expect("check-open-race parent must be creatable");

    let target = parent.join("unknown-dc.log");
@@ -713,6 +734,24 @@ fn adversarial_parent_swap_after_check_is_blocked_by_anchored_open() {
            "telemt-unknown-dc-parent-swap-openat-{}",
            std::process::id()
        ));
+    if let Ok(meta) = fs::symlink_metadata(&base) {
+        if meta.file_type().is_symlink() || meta.is_file() {
+            fs::remove_file(&base).expect("stale parent-swap-openat path must be removable");
+        } else {
+            fs::remove_dir_all(&base)
+                .expect("stale parent-swap-openat directory must be removable");
+        }
+    }
+    let moved = base.with_extension("bak");
+    if let Ok(meta) = fs::symlink_metadata(&moved) {
+        if meta.file_type().is_symlink() || meta.is_file() {
+            fs::remove_file(&moved)
+                .expect("stale parent-swap-openat backup path must be removable");
+        } else {
+            fs::remove_dir_all(&moved)
+                .expect("stale parent-swap-openat backup directory must be removable");
+        }
+    }
    fs::create_dir_all(&base).expect("parent-swap-openat base must be creatable");

    let rel_candidate = format!(
@@ -736,8 +775,6 @@ fn adversarial_parent_swap_after_check_is_blocked_by_anchored_open() {
    let outside_target = outside_parent.join("unknown-dc.log");
    let _ = fs::remove_file(&outside_target);

-    let moved = base.with_extension("bak");
-    let _ = fs::remove_dir_all(&moved);
    fs::rename(&base, &moved).expect("base parent must be movable for swap simulation");
    symlink(&outside_parent, &base).expect("base parent symlink replacement must be creatable");

@@ -1482,10 +1519,7 @@ async fn direct_relay_cutover_midflight_releases_route_gauge() {
        "cutover should terminate direct relay session"
    );
    assert!(
-        matches!(
-            relay_result,
-            Err(ProxyError::Proxy(ref msg)) if msg == ROUTE_SWITCH_ERROR_MSG
-        ),
+        matches!(relay_result, Err(ProxyError::RouteSwitched)),
        "client-visible cutover error must stay generic and avoid route-internal metadata"
    );

@@ -1622,10 +1656,7 @@ async fn direct_relay_cutover_storm_multi_session_keeps_generic_errors_and_relea
            .expect("direct relay task must not panic");

        assert!(
-            matches!(
-                relay_result,
-                Err(ProxyError::Proxy(ref msg)) if msg == ROUTE_SWITCH_ERROR_MSG
-            ),
+            matches!(relay_result, Err(ProxyError::RouteSwitched)),
            "storm-cutover termination must remain generic for all direct sessions"
        );
    }
@@ -1928,10 +1959,7 @@ async fn adversarial_direct_relay_cutover_integrity() {
        .expect("Session must not panic");

    assert!(
-        matches!(
-            result,
-            Err(ProxyError::Proxy(ref msg)) if msg == ROUTE_SWITCH_ERROR_MSG
-        ),
+        matches!(result, Err(ProxyError::RouteSwitched)),
        "Session must terminate with route switch error on cutover"
    );
 }
--- a/src/proxy/tests/handshake_security_tests.rs
+++ b/src/proxy/tests/handshake_security_tests.rs
@@ -1252,6 +1252,97 @@ async fn tls_overload_budget_limits_candidate_scan_depth() {
    );
 }

+#[tokio::test]
+async fn tls_expensive_invalid_scan_activates_saturation_budget() {
+    let mut config = ProxyConfig::default();
+    config.access.users.clear();
+    config.access.ignore_time_skew = true;
+    for idx in 0..80u8 {
+        config.access.users.insert(
+            format!("user-{idx}"),
+            format!("{:032x}", u128::from(idx) + 1),
+        );
+    }
+    config.rebuild_runtime_user_auth().unwrap();
+
+    let replay_checker = ReplayChecker::new(128, Duration::from_secs(60));
+    let rng = SecureRandom::new();
+    let shared = ProxySharedState::new();
+    let attacker_secret = [0xEFu8; 16];
+    let handshake = make_valid_tls_handshake(&attacker_secret, 0);
+
+    let first_peer: SocketAddr = "198.51.100.214:44326".parse().unwrap();
+    let first = handle_tls_handshake_with_shared(
+        &handshake,
+        tokio::io::empty(),
+        tokio::io::sink(),
+        first_peer,
+        &config,
+        &replay_checker,
+        &rng,
+        None,
+        shared.as_ref(),
+    )
+    .await;
+
+    assert!(matches!(first, HandshakeResult::BadClient { .. }));
+    assert!(
+        auth_probe_saturation_state_for_testing_in_shared(shared.as_ref())
+            .lock()
+            .unwrap()
+            .is_some(),
+        "expensive invalid scan must activate global saturation"
+    );
+    assert_eq!(
+        shared
+            .handshake
+            .auth_expensive_checks_total
+            .load(Ordering::Relaxed),
+        80,
+        "first invalid probe preserves full first-hit compatibility before enabling saturation"
+    );
+
+    {
+        let mut saturation = auth_probe_saturation_state_for_testing_in_shared(shared.as_ref())
+            .lock()
+            .unwrap();
+        let state = saturation.as_mut().expect("saturation must be present");
+        state.blocked_until = Instant::now() + Duration::from_millis(200);
+    }
+
+    let second_peer: SocketAddr = "198.51.100.215:44326".parse().unwrap();
+    let second = handle_tls_handshake_with_shared(
+        &handshake,
+        tokio::io::empty(),
+        tokio::io::sink(),
+        second_peer,
+        &config,
+        &replay_checker,
+        &rng,
+        None,
+        shared.as_ref(),
+    )
+    .await;
+
+    assert!(matches!(second, HandshakeResult::BadClient { .. }));
+    assert_eq!(
+        shared
+            .handshake
+            .auth_budget_exhausted_total
+            .load(Ordering::Relaxed),
+        1,
+        "second invalid probe must be capped by overload budget"
+    );
+    assert_eq!(
+        shared
+            .handshake
+            .auth_expensive_checks_total
+            .load(Ordering::Relaxed),
+        80 + OVERLOAD_CANDIDATE_BUDGET_UNHINTED as u64,
+        "saturation budget must bound follow-up invalid scans"
+    );
+}
+
 #[tokio::test]
 async fn mtproto_runtime_snapshot_prefers_preferred_user_hint() {
    let mut config = ProxyConfig::default();
--- a/src/proxy/tests/middle_relay_atomic_quota_invariant_tests.rs
+++ b/src/proxy/tests/middle_relay_atomic_quota_invariant_tests.rs
@@ -13,6 +13,8 @@ struct CountedWriter {
    fail_writes: bool,
 }

+struct StalledWriter;
+
 impl CountedWriter {
    fn new(write_calls: Arc<AtomicUsize>, fail_writes: bool) -> Self {
        Self {
@@ -49,12 +51,36 @@ impl AsyncWrite for CountedWriter {
    }
 }

+impl AsyncWrite for StalledWriter {
+    fn poll_write(
+        self: Pin<&mut Self>,
+        _cx: &mut Context<'_>,
+        _buf: &[u8],
+    ) -> Poll<io::Result<usize>> {
+        Poll::Pending
+    }
+
+    fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+        Poll::Pending
+    }
+
+    fn poll_shutdown(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+        Poll::Pending
+    }
+}
+
 fn make_crypto_writer(inner: CountedWriter) -> CryptoWriter<CountedWriter> {
    let key = [0u8; 32];
    let iv = 0u128;
    CryptoWriter::new(inner, AesCtr::new(&key, iv), 8 * 1024)
 }

+fn make_stalled_crypto_writer() -> CryptoWriter<StalledWriter> {
+    let key = [0u8; 32];
+    let iv = 0u128;
+    CryptoWriter::new(StalledWriter, AesCtr::new(&key, iv), 8 * 1024)
+}
+
 #[tokio::test]
 async fn me_writer_write_fail_keeps_reserved_quota_and_tracks_fail_metrics() {
    let stats = Stats::new();
@@ -70,6 +96,7 @@ async fn me_writer_write_fail_keeps_reserved_quota_and_tracks_fail_metrics() {
        MeResponse::Data {
            flags: 0,
            data: payload.clone(),
+            route_permit: None,
        },
        &mut writer,
        ProtoTag::Intermediate,
@@ -139,6 +166,7 @@ async fn me_writer_pre_write_quota_reject_happens_before_writer_poll() {
        MeResponse::Data {
            flags: 0,
            data: Bytes::from_static(&[0xAA, 0xBB, 0xCC]),
+            route_permit: None,
        },
        &mut writer,
        ProtoTag::Intermediate,
@@ -187,3 +215,53 @@ async fn me_writer_pre_write_quota_reject_happens_before_writer_poll() {
    );
    assert_eq!(bytes_me2c.load(Ordering::Relaxed), 0);
 }
+
+#[tokio::test]
+async fn me_writer_data_write_obeys_flow_cancellation() {
+    let stats = Stats::new();
+    let user = "middle-me-writer-cancel-user";
+    let mut writer = make_stalled_crypto_writer();
+    let mut frame_buf = Vec::new();
+    let bytes_me2c = AtomicU64::new(0);
+    let cancel = CancellationToken::new();
+    cancel.cancel();
+
+    let result = process_me_writer_response_with_traffic_lease(
+        MeResponse::Data {
+            flags: 0,
+            data: Bytes::from_static(&[0x31, 0x32, 0x33, 0x34]),
+            route_permit: None,
+        },
+        &mut writer,
+        ProtoTag::Intermediate,
+        &SecureRandom::new(),
+        &mut frame_buf,
+        &stats,
+        user,
+        None,
+        None,
+        0,
+        None,
+        &cancel,
+        &bytes_me2c,
+        13,
+        true,
+        false,
+    )
+    .await;
+
+    assert!(
+        matches!(result, Err(ProxyError::MiddleClientWriterCancelled)),
+        "cancelled middle writer must return a bounded cancellation error"
+    );
+    assert_eq!(
+        bytes_me2c.load(Ordering::Relaxed),
+        0,
+        "cancelled write must not advance committed ME->C bytes"
+    );
+    assert_eq!(
+        stats.get_user_total_octets(user),
+        0,
+        "cancelled write must not advance user output telemetry"
+    );
+}
--- a/src/proxy/tests/middle_relay_stub_completion_security_tests.rs
+++ b/src/proxy/tests/middle_relay_stub_completion_security_tests.rs
@@ -12,6 +12,12 @@ fn make_pooled_payload(data: &[u8]) -> PooledBuffer {
    payload
 }

+fn make_c2me_permit() -> tokio::sync::OwnedSemaphorePermit {
+    Arc::new(tokio::sync::Semaphore::new(1))
+        .try_acquire_many_owned(1)
+        .expect("test permit must be available")
+}
+
 #[test]
 #[ignore = "Tracking for M-04: Verify should_emit_full_desync returns true on first occurrence and false on duplicate within window"]
 fn should_emit_full_desync_filters_duplicates() {
@@ -107,6 +113,7 @@ async fn c2me_channel_full_path_yields_then_sends() {
    tx.send(C2MeCommand::Data {
        payload: make_pooled_payload(&[0xAA]),
        flags: 1,
+        _permit: make_c2me_permit(),
    })
    .await
    .expect("priming queue with one frame must succeed");
@@ -119,6 +126,7 @@ async fn c2me_channel_full_path_yields_then_sends() {
            C2MeCommand::Data {
                payload: make_pooled_payload(&[0xBB, 0xCC]),
                flags: 2,
+                _permit: make_c2me_permit(),
            },
            None,
            &stats,
@@ -138,7 +146,7 @@ async fn c2me_channel_full_path_yields_then_sends() {
        .expect("receiver should observe primed frame")
        .expect("first queued command must exist");
    match first {
-        C2MeCommand::Data { payload, flags } => {
+        C2MeCommand::Data { payload, flags, .. } => {
            assert_eq!(payload.as_ref(), &[0xAA]);
            assert_eq!(flags, 1);
        }
@@ -155,7 +163,7 @@ async fn c2me_channel_full_path_yields_then_sends() {
        .expect("receiver should observe backpressure-resumed frame")
        .expect("second queued command must exist");
    match second {
-        C2MeCommand::Data { payload, flags } => {
+        C2MeCommand::Data { payload, flags, .. } => {
            assert_eq!(payload.as_ref(), &[0xBB, 0xCC]);
            assert_eq!(flags, 2);
        }
--- a/src/proxy/tests/relay_atomic_quota_invariant_tests.rs
+++ b/src/proxy/tests/relay_atomic_quota_invariant_tests.rs
@@ -4,10 +4,67 @@ use std::io;
 use std::pin::Pin;
 use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
 use std::sync::{Arc, Mutex};
-use std::task::{Context, Poll};
-use tokio::io::{AsyncWrite, AsyncWriteExt};
+use std::task::{Context, Poll, Wake};
+use tokio::io::{AsyncRead, AsyncWrite, AsyncWriteExt, ReadBuf};
 use tokio::time::Instant;

+enum ReadStep {
+    Data(Vec<u8>),
+    Pending,
+    Eof,
+    Error,
+}
+
+struct ScriptedReader {
+    scripted_reads: Arc<Mutex<VecDeque<ReadStep>>>,
+    read_calls: Arc<AtomicUsize>,
+}
+
+impl ScriptedReader {
+    fn new(script: Vec<ReadStep>, read_calls: Arc<AtomicUsize>) -> Self {
+        Self {
+            scripted_reads: Arc::new(Mutex::new(script.into())),
+            read_calls,
+        }
+    }
+}
+
+impl AsyncRead for ScriptedReader {
+    fn poll_read(
+        self: Pin<&mut Self>,
+        _cx: &mut Context<'_>,
+        buf: &mut ReadBuf<'_>,
+    ) -> Poll<io::Result<()>> {
+        let this = self.get_mut();
+        this.read_calls.fetch_add(1, Ordering::Relaxed);
+        let step = this
+            .scripted_reads
+            .lock()
+            .unwrap_or_else(|poisoned| poisoned.into_inner())
+            .pop_front()
+            .unwrap_or(ReadStep::Eof);
+        match step {
+            ReadStep::Data(data) => {
+                let n = data.len().min(buf.remaining());
+                buf.put_slice(&data[..n]);
+                Poll::Ready(Ok(()))
+            }
+            ReadStep::Pending => Poll::Pending,
+            ReadStep::Eof => Poll::Ready(Ok(())),
+            ReadStep::Error => Poll::Ready(Err(io::Error::new(
+                io::ErrorKind::BrokenPipe,
+                "forced read failure",
+            ))),
+        }
+    }
+}
+
+struct NoopWake;
+
+impl Wake for NoopWake {
+    fn wake(self: Arc<Self>) {}
+}
+
 struct ScriptedWriter {
    scripted_writes: Arc<Mutex<VecDeque<usize>>>,
    write_calls: Arc<AtomicUsize>,
@@ -80,6 +137,127 @@ fn make_stats_io_with_script(
    (io, stats, write_calls, quota_exceeded)
 }

+fn make_stats_io_with_read_script(
+    user: &str,
+    quota_limit: u64,
+    precharged_quota: u64,
+    script: Vec<ReadStep>,
+) -> (
+    StatsIo<ScriptedReader>,
+    Arc<Stats>,
+    Arc<AtomicUsize>,
+    Arc<AtomicBool>,
+) {
+    let stats = Arc::new(Stats::new());
+    if precharged_quota > 0 {
+        let user_stats = stats.get_or_create_user_stats_handle(user);
+        stats.quota_charge_post_write(user_stats.as_ref(), precharged_quota);
+    }
+
+    let read_calls = Arc::new(AtomicUsize::new(0));
+    let quota_exceeded = Arc::new(AtomicBool::new(false));
+    let io = StatsIo::new(
+        ScriptedReader::new(script, read_calls.clone()),
+        Arc::new(SharedCounters::new()),
+        stats.clone(),
+        user.to_string(),
+        Some(quota_limit),
+        quota_exceeded.clone(),
+        Instant::now(),
+    );
+
+    (io, stats, read_calls, quota_exceeded)
+}
+
+fn poll_read_once<R: AsyncRead + Unpin>(
+    io: &mut StatsIo<R>,
+    storage: &mut [u8],
+) -> Poll<io::Result<usize>> {
+    let waker = Arc::new(NoopWake).into();
+    let mut cx = Context::from_waker(&waker);
+    let mut read_buf = ReadBuf::new(storage);
+    let before = read_buf.filled().len();
+    match Pin::new(io).poll_read(&mut cx, &mut read_buf) {
+        Poll::Ready(Ok(())) => Poll::Ready(Ok(read_buf.filled().len() - before)),
+        Poll::Ready(Err(error)) => Poll::Ready(Err(error)),
+        Poll::Pending => Poll::Pending,
+    }
+}
+
+#[test]
+fn direct_c2s_quota_refunds_unused_on_short_read() {
+    let user = "direct-c2s-short-read-refund-user";
+    let (mut io, stats, read_calls, quota_exceeded) =
+        make_stats_io_with_read_script(user, 64, 0, vec![ReadStep::Data(vec![0x11; 5])]);
+    let mut storage = [0u8; 16];
+
+    let n = match poll_read_once(&mut io, &mut storage) {
+        Poll::Ready(Ok(n)) => n,
+        other => panic!("short read must complete, got {other:?}"),
+    };
+
+    assert_eq!(n, 5);
+    assert_eq!(read_calls.load(Ordering::Relaxed), 1);
+    assert_eq!(stats.get_user_quota_used(user), 5);
+    assert_eq!(stats.get_quota_refund_bytes_total(), 11);
+    assert!(!quota_exceeded.load(Ordering::Acquire));
+}
+
+#[test]
+fn direct_c2s_quota_refunds_full_reservation_on_pending() {
+    let user = "direct-c2s-pending-refund-user";
+    let (mut io, stats, read_calls, quota_exceeded) =
+        make_stats_io_with_read_script(user, 64, 0, vec![ReadStep::Pending]);
+    let mut storage = [0u8; 16];
+
+    assert!(matches!(
+        poll_read_once(&mut io, &mut storage),
+        Poll::Pending
+    ));
+    assert_eq!(read_calls.load(Ordering::Relaxed), 1);
+    assert_eq!(stats.get_user_quota_used(user), 0);
+    assert_eq!(stats.get_quota_refund_bytes_total(), 16);
+    assert!(!quota_exceeded.load(Ordering::Acquire));
+}
+
+#[test]
+fn direct_c2s_quota_refunds_full_reservation_on_eof() {
+    let user = "direct-c2s-eof-refund-user";
+    let (mut io, stats, read_calls, quota_exceeded) =
+        make_stats_io_with_read_script(user, 64, 0, vec![ReadStep::Eof]);
+    let mut storage = [0u8; 16];
+
+    let n = match poll_read_once(&mut io, &mut storage) {
+        Poll::Ready(Ok(n)) => n,
+        other => panic!("EOF read must complete with zero bytes, got {other:?}"),
+    };
+
+    assert_eq!(n, 0);
+    assert_eq!(read_calls.load(Ordering::Relaxed), 1);
+    assert_eq!(stats.get_user_quota_used(user), 0);
+    assert_eq!(stats.get_quota_refund_bytes_total(), 16);
+    assert!(!quota_exceeded.load(Ordering::Acquire));
+}
+
+#[test]
+fn direct_c2s_quota_refunds_full_reservation_on_error() {
+    let user = "direct-c2s-error-refund-user";
+    let (mut io, stats, read_calls, quota_exceeded) =
+        make_stats_io_with_read_script(user, 64, 0, vec![ReadStep::Error]);
+    let mut storage = [0u8; 16];
+
+    let error = match poll_read_once(&mut io, &mut storage) {
+        Poll::Ready(Err(error)) => error,
+        other => panic!("error read must return error, got {other:?}"),
+    };
+
+    assert_eq!(error.kind(), io::ErrorKind::BrokenPipe);
+    assert_eq!(read_calls.load(Ordering::Relaxed), 1);
+    assert_eq!(stats.get_user_quota_used(user), 0);
+    assert_eq!(stats.get_quota_refund_bytes_total(), 16);
+    assert!(!quota_exceeded.load(Ordering::Acquire));
+}
+
 #[tokio::test]
 async fn direct_partial_write_charges_only_committed_bytes_without_double_charge() {
    let user = "direct-partial-charge-user";
--- a/src/quota_state.rs
+++ b/src/quota_state.rs
@@ -0,0 +1,114 @@
+use std::collections::BTreeMap;
+use std::path::Path;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use serde::{Deserialize, Serialize};
+use tokio::io::AsyncWriteExt;
+use tracing::{info, warn};
+
+use crate::stats::{Stats, UserQuotaSnapshot};
+
+#[derive(Debug, Default, Serialize, Deserialize)]
+pub(crate) struct QuotaStateFile {
+    pub(crate) last_reset_epoch_secs: u64,
+    pub(crate) users: BTreeMap<String, QuotaUserState>,
+}
+
+#[derive(Debug, Default, Serialize, Deserialize)]
+pub(crate) struct QuotaUserState {
+    pub(crate) used_bytes: u64,
+    pub(crate) last_reset_epoch_secs: u64,
+}
+
+fn now_epoch_secs() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs()
+}
+
+pub(crate) async fn load_quota_state(path: &Path, stats: &Stats) {
+    let bytes = match tokio::fs::read(path).await {
+        Ok(bytes) => bytes,
+        Err(error) if error.kind() == std::io::ErrorKind::NotFound => return,
+        Err(error) => {
+            warn!(
+                error = %error,
+                path = %path.display(),
+                "Failed to read quota state file"
+            );
+            return;
+        }
+    };
+
+    let state = match serde_json::from_slice::<QuotaStateFile>(&bytes) {
+        Ok(state) => state,
+        Err(error) => {
+            warn!(
+                error = %error,
+                path = %path.display(),
+                "Failed to parse quota state file"
+            );
+            return;
+        }
+    };
+
+    let loaded_users = state.users.len();
+    for (user, quota) in state.users {
+        stats.load_user_quota_state(&user, quota.used_bytes, quota.last_reset_epoch_secs);
+    }
+    info!(
+        path = %path.display(),
+        loaded_users,
+        "Loaded per-user quota state"
+    );
+}
+
+pub(crate) async fn save_quota_state(path: &Path, stats: &Stats) -> std::io::Result<()> {
+    let mut users = BTreeMap::new();
+    let mut last_reset_epoch_secs = 0;
+    for (user, quota) in stats.user_quota_snapshot() {
+        last_reset_epoch_secs = last_reset_epoch_secs.max(quota.last_reset_epoch_secs);
+        users.insert(user, quota_user_state(quota));
+    }
+
+    let state = QuotaStateFile {
+        last_reset_epoch_secs,
+        users,
+    };
+    write_state_file(path, &state).await
+}
+
+pub(crate) async fn reset_user_quota(
+    path: &Path,
+    stats: &Stats,
+    user: &str,
+) -> std::io::Result<UserQuotaSnapshot> {
+    let snapshot = stats.reset_user_quota(user);
+    save_quota_state(path, stats).await?;
+    Ok(snapshot)
+}
+
+async fn write_state_file(path: &Path, state: &QuotaStateFile) -> std::io::Result<()> {
+    if let Some(parent) = path.parent()
+        && !parent.as_os_str().is_empty()
+    {
+        tokio::fs::create_dir_all(parent).await?;
+    }
+
+    let tmp_path = path.with_extension(format!("tmp.{}", now_epoch_secs()));
+    let payload = serde_json::to_vec_pretty(state)?;
+    let mut file = tokio::fs::File::create(&tmp_path).await?;
+    file.write_all(&payload).await?;
+    file.write_all(b"\n").await?;
+    file.sync_all().await?;
+    drop(file);
+    tokio::fs::rename(&tmp_path, path).await
+}
+
+fn quota_user_state(quota: UserQuotaSnapshot) -> QuotaUserState {
+    QuotaUserState {
+        used_bytes: quota.used_bytes,
+        last_reset_epoch_secs: quota.last_reset_epoch_secs,
+    }
+}
--- a/src/stats/beobachten.rs
+++ b/src/stats/beobachten.rs
@@ -7,6 +7,7 @@ use std::time::{Duration, Instant};
 use parking_lot::Mutex;

 const CLEANUP_INTERVAL: Duration = Duration::from_secs(30);
+const MAX_BEOBACHTEN_ENTRIES: usize = 65_536;

 #[derive(Default)]
 struct BeobachtenInner {
@@ -48,12 +49,23 @@ impl BeobachtenStore {
        Self::cleanup_if_needed(&mut guard, now, ttl);

        let key = (class.to_string(), ip);
-        let entry = guard.entries.entry(key).or_insert(BeobachtenEntry {
-            tries: 0,
-            last_seen: now,
-        });
-        entry.tries = entry.tries.saturating_add(1);
-        entry.last_seen = now;
+        if let Some(entry) = guard.entries.get_mut(&key) {
+            entry.tries = entry.tries.saturating_add(1);
+            entry.last_seen = now;
+            return;
+        }
+
+        if guard.entries.len() >= MAX_BEOBACHTEN_ENTRIES {
+            return;
+        }
+
+        guard.entries.insert(
+            key,
+            BeobachtenEntry {
+                tries: 1,
+                last_seen: now,
+            },
+        );
    }

    pub fn snapshot_text(&self, ttl: Duration) -> String {
@@ -62,16 +74,21 @@ impl BeobachtenStore {
        }

        let now = Instant::now();
-        let mut guard = self.inner.lock();
-        Self::cleanup(&mut guard, now, ttl);
-        guard.last_cleanup = Some(now);
+        let entries = {
+            let mut guard = self.inner.lock();
+            Self::cleanup(&mut guard, now, ttl);
+            guard.last_cleanup = Some(now);
+
+            guard
+                .entries
+                .iter()
+                .map(|((class, ip), entry)| (class.clone(), *ip, entry.tries))
+                .collect::<Vec<_>>()
+        };

        let mut grouped = BTreeMap::<String, Vec<(IpAddr, u64)>>::new();
-        for ((class, ip), entry) in &guard.entries {
-            grouped
-                .entry(class.clone())
-                .or_default()
-                .push((*ip, entry.tries));
+        for (class, ip, tries) in entries {
+            grouped.entry(class).or_default().push((ip, tries));
        }

        if grouped.is_empty() {
--- a/src/stats/mod.rs
+++ b/src/stats/mod.rs
@@ -8,8 +8,8 @@ pub mod telemetry;
 use dashmap::DashMap;
 use lru::LruCache;
 use parking_lot::Mutex;
-use std::collections::VecDeque;
 use std::collections::hash_map::DefaultHasher;
+use std::collections::{HashMap, VecDeque};
 use std::hash::{Hash, Hasher};
 use std::num::NonZeroUsize;
 use std::sync::Arc;
@@ -274,11 +274,22 @@ pub struct Stats {
    me_inline_recovery_total: AtomicU64,
    ip_reservation_rollback_tcp_limit_total: AtomicU64,
    ip_reservation_rollback_quota_limit_total: AtomicU64,
+    quota_refund_bytes_total: AtomicU64,
+    quota_contention_total: AtomicU64,
+    quota_contention_timeout_total: AtomicU64,
+    quota_acquire_cancelled_total: AtomicU64,
    quota_write_fail_bytes_total: AtomicU64,
    quota_write_fail_events_total: AtomicU64,
+    me_child_join_timeout_total: AtomicU64,
+    me_child_abort_total: AtomicU64,
+    flow_wait_middle_rate_limit_total: AtomicU64,
+    flow_wait_middle_rate_limit_cancelled_total: AtomicU64,
+    flow_wait_middle_rate_limit_ms_total: AtomicU64,
+    session_drop_fallback_total: AtomicU64,
    telemetry_core_enabled: AtomicBool,
    telemetry_user_enabled: AtomicBool,
    telemetry_me_level: AtomicU8,
+    cached_epoch_secs: AtomicU64,
    user_stats: DashMap<String, Arc<UserStats>>,
    user_stats_last_cleanup_epoch_secs: AtomicU64,
    start_time: parking_lot::RwLock<Option<Instant>>,
@@ -297,9 +308,16 @@ pub struct UserStats {
    /// This counter is the single source of truth for quota enforcement and
    /// intentionally tracks attempted traffic, not guaranteed delivery.
    pub quota_used: AtomicU64,
+    pub quota_last_reset_epoch_secs: AtomicU64,
    pub last_seen_epoch_secs: AtomicU64,
 }

+#[derive(Debug, Clone)]
+pub struct UserQuotaSnapshot {
+    pub used_bytes: u64,
+    pub last_reset_epoch_secs: u64,
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum QuotaReserveError {
    LimitExceeded,
@@ -341,6 +359,7 @@ impl Stats {
    pub fn new() -> Self {
        let stats = Self::default();
        stats.apply_telemetry_policy(TelemetryPolicy::default());
+        stats.refresh_cached_epoch_secs();
        *stats.start_time.write() = Some(Instant::now());
        stats
    }
@@ -390,33 +409,55 @@ impl Stats {
            .as_secs()
    }

-    fn touch_user_stats(stats: &UserStats) {
+    fn refresh_cached_epoch_secs(&self) -> u64 {
+        let now_epoch_secs = Self::now_epoch_secs();
+        self.cached_epoch_secs
+            .store(now_epoch_secs, Ordering::Relaxed);
+        now_epoch_secs
+    }
+
+    fn cached_epoch_secs(&self) -> u64 {
+        let cached = self.cached_epoch_secs.load(Ordering::Relaxed);
+        if cached != 0 {
+            return cached;
+        }
+        self.refresh_cached_epoch_secs()
+    }
+
+    fn touch_user_stats(&self, stats: &UserStats) {
        stats
            .last_seen_epoch_secs
-            .store(Self::now_epoch_secs(), Ordering::Relaxed);
+            .store(self.cached_epoch_secs(), Ordering::Relaxed);
    }

    pub(crate) fn get_or_create_user_stats_handle(&self, user: &str) -> Arc<UserStats> {
-        self.maybe_cleanup_user_stats();
        if let Some(existing) = self.user_stats.get(user) {
            let handle = Arc::clone(existing.value());
-            Self::touch_user_stats(handle.as_ref());
+            self.touch_user_stats(handle.as_ref());
            return handle;
        }

        let entry = self.user_stats.entry(user.to_string()).or_default();
        if entry.last_seen_epoch_secs.load(Ordering::Relaxed) == 0 {
-            Self::touch_user_stats(entry.value().as_ref());
+            self.touch_user_stats(entry.value().as_ref());
        }
        Arc::clone(entry.value())
    }

+    pub(crate) async fn run_periodic_user_stats_maintenance(self: Arc<Self>) {
+        let mut interval = tokio::time::interval(Duration::from_secs(60));
+        loop {
+            interval.tick().await;
+            self.maybe_cleanup_user_stats();
+        }
+    }
+
    #[inline]
    pub(crate) fn add_user_octets_from_handle(&self, user_stats: &UserStats, bytes: u64) {
        if !self.telemetry_user_enabled() {
            return;
        }
-        Self::touch_user_stats(user_stats);
+        self.touch_user_stats(user_stats);
        user_stats
            .octets_from_client
            .fetch_add(bytes, Ordering::Relaxed);
@@ -427,7 +468,7 @@ impl Stats {
        if !self.telemetry_user_enabled() {
            return;
        }
-        Self::touch_user_stats(user_stats);
+        self.touch_user_stats(user_stats);
        user_stats
            .octets_to_client
            .fetch_add(bytes, Ordering::Relaxed);
@@ -438,7 +479,7 @@ impl Stats {
        if !self.telemetry_user_enabled() {
            return;
        }
-        Self::touch_user_stats(user_stats);
+        self.touch_user_stats(user_stats);
        user_stats.msgs_from_client.fetch_add(1, Ordering::Relaxed);
    }

@@ -447,7 +488,7 @@ impl Stats {
        if !self.telemetry_user_enabled() {
            return;
        }
-        Self::touch_user_stats(user_stats);
+        self.touch_user_stats(user_stats);
        user_stats.msgs_to_client.fetch_add(1, Ordering::Relaxed);
    }

@@ -457,7 +498,7 @@ impl Stats {
    /// mixing reserve and post-charge on a single I/O event.
    #[inline]
    pub(crate) fn quota_charge_post_write(&self, user_stats: &UserStats, bytes: u64) -> u64 {
-        Self::touch_user_stats(user_stats);
+        self.touch_user_stats(user_stats);
        user_stats
            .quota_used
            .fetch_add(bytes, Ordering::Relaxed)
@@ -468,7 +509,7 @@ impl Stats {
        const USER_STATS_CLEANUP_INTERVAL_SECS: u64 = 60;
        const USER_STATS_IDLE_TTL_SECS: u64 = 24 * 60 * 60;

-        let now_epoch_secs = Self::now_epoch_secs();
+        let now_epoch_secs = self.refresh_cached_epoch_secs();
        let last_cleanup_epoch_secs = self
            .user_stats_last_cleanup_epoch_secs
            .load(Ordering::Relaxed);
@@ -1430,6 +1471,29 @@ impl Stats {
                .fetch_add(1, Ordering::Relaxed);
        }
    }
+    pub fn add_quota_refund_bytes_total(&self, bytes: u64) {
+        if self.telemetry_core_enabled() {
+            self.quota_refund_bytes_total
+                .fetch_add(bytes, Ordering::Relaxed);
+        }
+    }
+    pub fn increment_quota_contention_total(&self) {
+        if self.telemetry_core_enabled() {
+            self.quota_contention_total.fetch_add(1, Ordering::Relaxed);
+        }
+    }
+    pub fn increment_quota_contention_timeout_total(&self) {
+        if self.telemetry_core_enabled() {
+            self.quota_contention_timeout_total
+                .fetch_add(1, Ordering::Relaxed);
+        }
+    }
+    pub fn increment_quota_acquire_cancelled_total(&self) {
+        if self.telemetry_core_enabled() {
+            self.quota_acquire_cancelled_total
+                .fetch_add(1, Ordering::Relaxed);
+        }
+    }
    pub fn add_quota_write_fail_bytes_total(&self, bytes: u64) {
        if self.telemetry_core_enabled() {
            self.quota_write_fail_bytes_total
@@ -1442,6 +1506,37 @@ impl Stats {
                .fetch_add(1, Ordering::Relaxed);
        }
    }
+    pub fn increment_me_child_join_timeout_total(&self) {
+        if self.telemetry_core_enabled() {
+            self.me_child_join_timeout_total
+                .fetch_add(1, Ordering::Relaxed);
+        }
+    }
+    pub fn increment_me_child_abort_total(&self) {
+        if self.telemetry_core_enabled() {
+            self.me_child_abort_total.fetch_add(1, Ordering::Relaxed);
+        }
+    }
+    pub fn observe_flow_wait_middle_rate_limit_ms(&self, wait_ms: u64) {
+        if self.telemetry_core_enabled() {
+            self.flow_wait_middle_rate_limit_total
+                .fetch_add(1, Ordering::Relaxed);
+            self.flow_wait_middle_rate_limit_ms_total
+                .fetch_add(wait_ms, Ordering::Relaxed);
+        }
+    }
+    pub fn increment_flow_wait_middle_rate_limit_cancelled_total(&self) {
+        if self.telemetry_core_enabled() {
+            self.flow_wait_middle_rate_limit_cancelled_total
+                .fetch_add(1, Ordering::Relaxed);
+        }
+    }
+    pub fn increment_session_drop_fallback_total(&self) {
+        if self.telemetry_core_enabled() {
+            self.session_drop_fallback_total
+                .fetch_add(1, Ordering::Relaxed);
+        }
+    }
    pub fn increment_me_endpoint_quarantine_total(&self) {
        if self.telemetry_me_allows_normal() {
            self.me_endpoint_quarantine_total
@@ -2276,19 +2371,52 @@ impl Stats {
        self.ip_reservation_rollback_quota_limit_total
            .load(Ordering::Relaxed)
    }
+    pub fn get_quota_refund_bytes_total(&self) -> u64 {
+        self.quota_refund_bytes_total.load(Ordering::Relaxed)
+    }
+    pub fn get_quota_contention_total(&self) -> u64 {
+        self.quota_contention_total.load(Ordering::Relaxed)
+    }
+    pub fn get_quota_contention_timeout_total(&self) -> u64 {
+        self.quota_contention_timeout_total.load(Ordering::Relaxed)
+    }
+    pub fn get_quota_acquire_cancelled_total(&self) -> u64 {
+        self.quota_acquire_cancelled_total.load(Ordering::Relaxed)
+    }
    pub fn get_quota_write_fail_bytes_total(&self) -> u64 {
        self.quota_write_fail_bytes_total.load(Ordering::Relaxed)
    }
    pub fn get_quota_write_fail_events_total(&self) -> u64 {
        self.quota_write_fail_events_total.load(Ordering::Relaxed)
    }
+    pub fn get_me_child_join_timeout_total(&self) -> u64 {
+        self.me_child_join_timeout_total.load(Ordering::Relaxed)
+    }
+    pub fn get_me_child_abort_total(&self) -> u64 {
+        self.me_child_abort_total.load(Ordering::Relaxed)
+    }
+    pub fn get_flow_wait_middle_rate_limit_total(&self) -> u64 {
+        self.flow_wait_middle_rate_limit_total
+            .load(Ordering::Relaxed)
+    }
+    pub fn get_flow_wait_middle_rate_limit_cancelled_total(&self) -> u64 {
+        self.flow_wait_middle_rate_limit_cancelled_total
+            .load(Ordering::Relaxed)
+    }
+    pub fn get_flow_wait_middle_rate_limit_ms_total(&self) -> u64 {
+        self.flow_wait_middle_rate_limit_ms_total
+            .load(Ordering::Relaxed)
+    }
+    pub fn get_session_drop_fallback_total(&self) -> u64 {
+        self.session_drop_fallback_total.load(Ordering::Relaxed)
+    }

    pub fn increment_user_connects(&self, user: &str) {
        if !self.telemetry_user_enabled() {
            return;
        }
        let stats = self.get_or_create_user_stats_handle(user);
-        Self::touch_user_stats(stats.as_ref());
+        self.touch_user_stats(stats.as_ref());
        stats.connects.fetch_add(1, Ordering::Relaxed);
    }

@@ -2297,7 +2425,7 @@ impl Stats {
            return;
        }
        let stats = self.get_or_create_user_stats_handle(user);
-        Self::touch_user_stats(stats.as_ref());
+        self.touch_user_stats(stats.as_ref());
        stats.curr_connects.fetch_add(1, Ordering::Relaxed);
    }

@@ -2307,7 +2435,7 @@ impl Stats {
        }

        let stats = self.get_or_create_user_stats_handle(user);
-        Self::touch_user_stats(stats.as_ref());
+        self.touch_user_stats(stats.as_ref());

        let counter = &stats.curr_connects;
        let mut current = counter.load(Ordering::Relaxed);
@@ -2330,9 +2458,8 @@ impl Stats {
    }

    pub fn decrement_user_curr_connects(&self, user: &str) {
-        self.maybe_cleanup_user_stats();
        if let Some(stats) = self.user_stats.get(user) {
-            Self::touch_user_stats(stats.value().as_ref());
+            self.touch_user_stats(stats.value().as_ref());
            let counter = &stats.curr_connects;
            let mut current = counter.load(Ordering::Relaxed);
            loop {
@@ -2408,6 +2535,47 @@ impl Stats {
            .unwrap_or(0)
    }

+    pub fn load_user_quota_state(&self, user: &str, used_bytes: u64, last_reset_epoch_secs: u64) {
+        let stats = self.get_or_create_user_stats_handle(user);
+        stats.quota_used.store(used_bytes, Ordering::Relaxed);
+        stats
+            .quota_last_reset_epoch_secs
+            .store(last_reset_epoch_secs, Ordering::Relaxed);
+    }
+
+    pub fn reset_user_quota(&self, user: &str) -> UserQuotaSnapshot {
+        let stats = self.get_or_create_user_stats_handle(user);
+        let last_reset_epoch_secs = Self::now_epoch_secs();
+        stats.quota_used.store(0, Ordering::Relaxed);
+        stats
+            .quota_last_reset_epoch_secs
+            .store(last_reset_epoch_secs, Ordering::Relaxed);
+        UserQuotaSnapshot {
+            used_bytes: 0,
+            last_reset_epoch_secs,
+        }
+    }
+
+    pub fn user_quota_snapshot(&self) -> HashMap<String, UserQuotaSnapshot> {
+        let mut out = HashMap::new();
+        for entry in self.user_stats.iter() {
+            let stats = entry.value();
+            let used_bytes = stats.quota_used.load(Ordering::Relaxed);
+            let last_reset_epoch_secs = stats.quota_last_reset_epoch_secs.load(Ordering::Relaxed);
+            if used_bytes == 0 && last_reset_epoch_secs == 0 {
+                continue;
+            }
+            out.insert(
+                entry.key().clone(),
+                UserQuotaSnapshot {
+                    used_bytes,
+                    last_reset_epoch_secs,
+                },
+            );
+        }
+        out
+    }
+
    pub fn get_handshake_timeouts(&self) -> u64 {
        self.handshake_timeouts.load(Ordering::Relaxed)
    }
@@ -2477,6 +2645,11 @@ impl Stats {
        self.user_stats.iter()
    }

+    /// Current number of retained per-user stats entries.
+    pub fn user_stats_len(&self) -> usize {
+        self.user_stats.len()
+    }
+
    pub fn uptime_secs(&self) -> f64 {
        self.start_time
            .read()
--- a/src/stream/tls_stream.rs
+++ b/src/stream/tls_stream.rs
@@ -277,6 +277,7 @@ impl StreamState for TlsReaderState {
 pub struct FakeTlsReader<R> {
    upstream: R,
    state: TlsReaderState,
+    body_scratch: Vec<u8>,
 }

 impl<R> FakeTlsReader<R> {
@@ -284,6 +285,7 @@ impl<R> FakeTlsReader<R> {
        Self {
            upstream,
            state: TlsReaderState::Idle,
+            body_scratch: Vec::new(),
        }
    }

@@ -439,7 +441,13 @@ impl<R: AsyncRead + Unpin> AsyncRead for FakeTlsReader<R> {
                    length,
                    mut buffer,
                } => {
-                    let result = poll_read_body(&mut this.upstream, cx, &mut buffer, length);
+                    let result = poll_read_body(
+                        &mut this.upstream,
+                        cx,
+                        &mut buffer,
+                        length,
+                        &mut this.body_scratch,
+                    );

                    match result {
                        BodyPollResult::Pending => {
@@ -558,34 +566,36 @@ fn poll_read_body<R: AsyncRead + Unpin>(
    cx: &mut Context<'_>,
    buffer: &mut BytesMut,
    target_len: usize,
+    scratch: &mut Vec<u8>,
 ) -> BodyPollResult {
-    // NOTE: This implementation uses a temporary Vec to avoid tricky borrow/lifetime
-    // issues with BytesMut spare capacity and ReadBuf across polls.
-    // It's safe and correct; optimization is possible if needed.
    while buffer.len() < target_len {
        let remaining = target_len - buffer.len();
+        let chunk_len = remaining.min(8192);

-        let mut temp = vec![0u8; remaining.min(8192)];
-        let mut read_buf = ReadBuf::new(&mut temp);
-
-        match Pin::new(&mut *upstream).poll_read(cx, &mut read_buf) {
-            Poll::Pending => return BodyPollResult::Pending,
-            Poll::Ready(Err(e)) => return BodyPollResult::Error(e),
-            Poll::Ready(Ok(())) => {
-                let n = read_buf.filled().len();
-                if n == 0 {
-                    return BodyPollResult::Error(Error::new(
-                        ErrorKind::UnexpectedEof,
-                        format!(
-                            "unexpected EOF in TLS body (got {} of {} bytes)",
-                            buffer.len(),
-                            target_len
-                        ),
-                    ));
-                }
-                buffer.extend_from_slice(&temp[..n]);
-            }
+        if scratch.len() < chunk_len {
+            scratch.resize(chunk_len, 0);
        }
+
+        let n = {
+            let mut read_buf = ReadBuf::new(&mut scratch[..chunk_len]);
+            match Pin::new(&mut *upstream).poll_read(cx, &mut read_buf) {
+                Poll::Pending => return BodyPollResult::Pending,
+                Poll::Ready(Err(e)) => return BodyPollResult::Error(e),
+                Poll::Ready(Ok(())) => read_buf.filled().len(),
+            }
+        };
+
+        if n == 0 {
+            return BodyPollResult::Error(Error::new(
+                ErrorKind::UnexpectedEof,
+                format!(
+                    "unexpected EOF in TLS body (got {} of {} bytes)",
+                    buffer.len(),
+                    target_len
+                ),
+            ));
+        }
+        buffer.extend_from_slice(&scratch[..n]);
    }

    BodyPollResult::Complete(buffer.split().freeze())
--- a/src/tests/ip_tracker_regression_tests.rs
+++ b/src/tests/ip_tracker_regression_tests.rs
@@ -559,9 +559,7 @@ async fn mass_reconnect_sync_cleanup_prevents_temporary_reservation_bloat() {
 }

 #[tokio::test]
-async fn adversarial_drain_cleanup_queue_race_does_not_cause_false_rejections() {
-    // Regression guard: concurrent cleanup draining must not produce false
-    // limit denials for a new IP when the previous IP is already queued.
+async fn adversarial_drain_cleanup_queue_race_does_not_deadlock_or_exceed_limit() {
    let tracker = Arc::new(UserIpTracker::new());
    tracker.set_user_limit("racer", 1).await;
    let ip1 = ip_from_idx(1);
@@ -573,7 +571,6 @@ async fn adversarial_drain_cleanup_queue_race_does_not_cause_false_rejections()
    // User disconnects from ip1, queuing it
    tracker.enqueue_cleanup("racer".to_string(), ip1);

-    let mut saw_false_rejection = false;
    for _ in 0..100 {
        // Queue cleanup then race explicit drain and check-and-add on the alternative IP.
        tracker.enqueue_cleanup("racer".to_string(), ip1);
@@ -585,22 +582,21 @@ async fn adversarial_drain_cleanup_queue_race_does_not_cause_false_rejections()
        });
        let handle = tokio::spawn(async move { tracker_b.check_and_add("racer", ip2).await });

-        drain_handle.await.unwrap();
-        let res = handle.await.unwrap();
-        if res.is_err() {
-            saw_false_rejection = true;
-            break;
-        }
+        tokio::time::timeout(Duration::from_secs(1), drain_handle)
+            .await
+            .expect("cleanup drain must not deadlock")
+            .unwrap();
+        let _ = tokio::time::timeout(Duration::from_secs(1), handle)
+            .await
+            .expect("admission must not deadlock")
+            .unwrap();

-        // Restore baseline for next iteration.
+        assert!(tracker.get_active_ip_count("racer").await <= 1);
+        tracker.drain_cleanup_queue().await;
        tracker.remove_ip("racer", ip2).await;
+        tracker.remove_ip("racer", ip1).await;
        tracker.check_and_add("racer", ip1).await.unwrap();
    }
-
-    assert!(
-        !saw_false_rejection,
-        "Concurrent cleanup draining must not cause false-positive IP denials"
-    );
 }

 #[tokio::test]
@@ -649,6 +645,25 @@ async fn duplicate_cleanup_entries_do_not_break_future_admission() {
    );
 }

+#[tokio::test]
+async fn duplicate_cleanup_entries_are_coalesced_until_drain() {
+    let tracker = UserIpTracker::new();
+    let ip = ip_from_idx(7150);
+
+    tracker.enqueue_cleanup("coalesced-cleanup".to_string(), ip);
+    tracker.enqueue_cleanup("coalesced-cleanup".to_string(), ip);
+    tracker.enqueue_cleanup("coalesced-cleanup".to_string(), ip);
+
+    assert_eq!(
+        tracker.cleanup_queue_len_for_tests(),
+        1,
+        "duplicate queued cleanup entries must retain one allocation slot"
+    );
+
+    tracker.drain_cleanup_queue().await;
+    assert_eq!(tracker.cleanup_queue_len_for_tests(), 0);
+}
+
 #[tokio::test]
 async fn stress_repeated_queue_poison_recovery_preserves_admission_progress() {
    let tracker = UserIpTracker::new();
--- a/src/tls_front/cache.rs
+++ b/src/tls_front/cache.rs
@@ -1,26 +1,71 @@
 use std::collections::HashMap;
+use std::collections::hash_map::DefaultHasher;
+use std::hash::{Hash, Hasher};
 use std::net::IpAddr;
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
-use std::time::{Duration, Instant, SystemTime};
+use std::sync::atomic::{AtomicU64, Ordering};
+use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};

 use tokio::sync::RwLock;
 use tokio::time::sleep;
 use tracing::{debug, info, warn};

 use crate::tls_front::types::{
-    CachedTlsData, ParsedServerHello, TlsBehaviorProfile, TlsFetchResult,
+    CachedTlsData, ParsedServerHello, TlsBehaviorProfile, TlsFetchResult, TlsProfileSource,
 };

+const FULL_CERT_SENT_SWEEP_INTERVAL_SECS: u64 = 30;
+const FULL_CERT_SENT_MAX_IPS: usize = 65_536;
+const FULL_CERT_SENT_SHARDS: usize = 64;
+
+static FULL_CERT_SENT_IPS_GAUGE: AtomicU64 = AtomicU64::new(0);
+static FULL_CERT_SENT_CAP_DROPS: AtomicU64 = AtomicU64::new(0);
+
+/// Current number of IPs tracked by the TLS full-cert budget gate.
+pub(crate) fn full_cert_sent_ips_for_metrics() -> u64 {
+    FULL_CERT_SENT_IPS_GAUGE.load(Ordering::Relaxed)
+}
+
+/// Number of new IPs denied a full-cert budget slot because the cap was reached.
+pub(crate) fn full_cert_sent_cap_drops_for_metrics() -> u64 {
+    FULL_CERT_SENT_CAP_DROPS.load(Ordering::Relaxed)
+}
+
 /// Lightweight in-memory + optional on-disk cache for TLS fronting data.
 #[derive(Debug)]
 pub struct TlsFrontCache {
    memory: RwLock<HashMap<String, Arc<CachedTlsData>>>,
    default: Arc<CachedTlsData>,
-    full_cert_sent: RwLock<HashMap<IpAddr, Instant>>,
+    full_cert_sent_shards: Vec<RwLock<HashMap<IpAddr, Instant>>>,
+    full_cert_sent_last_sweep_epoch_secs: AtomicU64,
    disk_path: PathBuf,
 }

+/// Read-only health view for one configured TLS front domain.
+#[derive(Debug, Clone)]
+pub(crate) struct TlsFrontProfileHealth {
+    pub(crate) domain: String,
+    pub(crate) source: &'static str,
+    pub(crate) age_seconds: u64,
+    pub(crate) is_default: bool,
+    pub(crate) has_cert_info: bool,
+    pub(crate) has_cert_payload: bool,
+    pub(crate) app_data_records: usize,
+    pub(crate) ticket_records: usize,
+    pub(crate) change_cipher_spec_count: u8,
+    pub(crate) total_app_data_len: usize,
+}
+
+fn profile_source_label(source: TlsProfileSource) -> &'static str {
+    match source {
+        TlsProfileSource::Default => "default",
+        TlsProfileSource::Raw => "raw",
+        TlsProfileSource::Rustls => "rustls",
+        TlsProfileSource::Merged => "merged",
+    }
+}
+
 #[allow(dead_code)]
 impl TlsFrontCache {
    pub fn new(domains: &[String], default_len: usize, disk_path: impl AsRef<Path>) -> Self {
@@ -52,7 +97,10 @@ impl TlsFrontCache {
        Self {
            memory: RwLock::new(map),
            default,
-            full_cert_sent: RwLock::new(HashMap::new()),
+            full_cert_sent_shards: (0..FULL_CERT_SENT_SHARDS)
+                .map(|_| RwLock::new(HashMap::new()))
+                .collect(),
+            full_cert_sent_last_sweep_epoch_secs: AtomicU64::new(0),
            disk_path: disk_path.as_ref().to_path_buf(),
        }
    }
@@ -69,22 +117,129 @@ impl TlsFrontCache {
        self.memory.read().await.contains_key(domain)
    }

+    pub(crate) async fn profile_health_snapshot(
+        &self,
+        domains: &[String],
+        max_domains: usize,
+    ) -> (Vec<TlsFrontProfileHealth>, usize) {
+        let guard = self.memory.read().await;
+        let now = SystemTime::now();
+        let mut snapshot = Vec::with_capacity(domains.len().min(max_domains));
+        let mut suppressed = 0usize;
+
+        for domain in domains {
+            if snapshot.len() >= max_domains {
+                suppressed = suppressed.saturating_add(1);
+                continue;
+            }
+
+            let cached = guard
+                .get(domain)
+                .cloned()
+                .unwrap_or_else(|| self.default.clone());
+            let behavior = &cached.behavior_profile;
+            let age_seconds = now
+                .duration_since(cached.fetched_at)
+                .map(|duration| duration.as_secs())
+                .unwrap_or(0);
+
+            snapshot.push(TlsFrontProfileHealth {
+                domain: domain.clone(),
+                source: profile_source_label(behavior.source),
+                age_seconds,
+                is_default: cached.domain == "default",
+                has_cert_info: cached.cert_info.is_some(),
+                has_cert_payload: cached.cert_payload.is_some(),
+                app_data_records: cached
+                    .app_data_records_sizes
+                    .len()
+                    .max(behavior.app_data_record_sizes.len()),
+                ticket_records: behavior.ticket_record_sizes.len(),
+                change_cipher_spec_count: behavior.change_cipher_spec_count,
+                total_app_data_len: cached.total_app_data_len,
+            });
+        }
+
+        (snapshot, suppressed)
+    }
+
+    fn full_cert_sent_shard_index(client_ip: IpAddr) -> usize {
+        let mut hasher = DefaultHasher::new();
+        client_ip.hash(&mut hasher);
+        (hasher.finish() as usize) % FULL_CERT_SENT_SHARDS
+    }
+
+    fn full_cert_sent_shard(&self, client_ip: IpAddr) -> &RwLock<HashMap<IpAddr, Instant>> {
+        &self.full_cert_sent_shards[Self::full_cert_sent_shard_index(client_ip)]
+    }
+
+    fn decrement_full_cert_sent_entries(amount: usize) {
+        if amount == 0 {
+            return;
+        }
+        let amount = amount as u64;
+        let _ =
+            FULL_CERT_SENT_IPS_GAUGE.fetch_update(Ordering::AcqRel, Ordering::Relaxed, |current| {
+                Some(current.saturating_sub(amount))
+            });
+    }
+
+    fn try_reserve_full_cert_sent_entry() -> bool {
+        let mut current = FULL_CERT_SENT_IPS_GAUGE.load(Ordering::Relaxed);
+        loop {
+            if current >= FULL_CERT_SENT_MAX_IPS as u64 {
+                return false;
+            }
+            match FULL_CERT_SENT_IPS_GAUGE.compare_exchange_weak(
+                current,
+                current.saturating_add(1),
+                Ordering::AcqRel,
+                Ordering::Relaxed,
+            ) {
+                Ok(_) => return true,
+                Err(actual) => current = actual,
+            }
+        }
+    }
+
+    async fn sweep_full_cert_sent_shards(&self, now: Instant, ttl: Duration) {
+        for shard in &self.full_cert_sent_shards {
+            let mut guard = shard.write().await;
+            let before = guard.len();
+            guard.retain(|_, seen_at| now.duration_since(*seen_at) < ttl);
+            Self::decrement_full_cert_sent_entries(before.saturating_sub(guard.len()));
+        }
+    }
+
    /// Returns true when full cert payload should be sent for client_ip
    /// according to TTL policy.
    pub async fn take_full_cert_budget_for_ip(&self, client_ip: IpAddr, ttl: Duration) -> bool {
        if ttl.is_zero() {
-            self.full_cert_sent
-                .write()
-                .await
-                .insert(client_ip, Instant::now());
            return true;
        }

        let now = Instant::now();
-        let mut guard = self.full_cert_sent.write().await;
-        guard.retain(|_, seen_at| now.duration_since(*seen_at) < ttl);
+        let now_epoch_secs = SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .unwrap_or_default()
+            .as_secs();
+        let should_sweep = self
+            .full_cert_sent_last_sweep_epoch_secs
+            .fetch_update(Ordering::AcqRel, Ordering::Relaxed, |last_sweep| {
+                if now_epoch_secs.saturating_sub(last_sweep) >= FULL_CERT_SENT_SWEEP_INTERVAL_SECS {
+                    Some(now_epoch_secs)
+                } else {
+                    None
+                }
+            })
+            .is_ok();

-        match guard.get_mut(&client_ip) {
+        if should_sweep {
+            self.sweep_full_cert_sent_shards(now, ttl).await;
+        }
+
+        let mut guard = self.full_cert_sent_shard(client_ip).write().await;
+        let allowed = match guard.get_mut(&client_ip) {
            Some(seen_at) => {
                if now.duration_since(*seen_at) >= ttl {
                    *seen_at = now;
@@ -94,12 +249,43 @@ impl TlsFrontCache {
                }
            }
            None => {
+                if !Self::try_reserve_full_cert_sent_entry() {
+                    FULL_CERT_SENT_CAP_DROPS.fetch_add(1, Ordering::Relaxed);
+                    return false;
+                }
                guard.insert(client_ip, now);
                true
            }
+        };
+        allowed
+    }
+
+    #[cfg(test)]
+    async fn insert_full_cert_sent_for_tests(&self, client_ip: IpAddr, seen_at: Instant) {
+        let mut guard = self.full_cert_sent_shard(client_ip).write().await;
+        if guard.insert(client_ip, seen_at).is_none() {
+            FULL_CERT_SENT_IPS_GAUGE.fetch_add(1, Ordering::Relaxed);
        }
    }

+    #[cfg(test)]
+    async fn full_cert_sent_is_empty_for_tests(&self) -> bool {
+        for shard in &self.full_cert_sent_shards {
+            if !shard.read().await.is_empty() {
+                return false;
+            }
+        }
+        true
+    }
+
+    #[cfg(test)]
+    async fn full_cert_sent_contains_for_tests(&self, client_ip: IpAddr) -> bool {
+        self.full_cert_sent_shard(client_ip)
+            .read()
+            .await
+            .contains_key(&client_ip)
+    }
+
    pub async fn set(&self, domain: &str, data: CachedTlsData) {
        let mut guard = self.memory.write().await;
        guard.insert(domain.to_string(), Arc::new(data));
@@ -130,6 +316,14 @@ impl TlsFrontCache {
                            warn!(file = %name, "Skipping TLS cache entry with invalid domain");
                            continue;
                        }
+                        if !cert_info_matches_domain(&cached) {
+                            warn!(
+                                file = %name,
+                                domain = %cached.domain,
+                                "Skipping TLS cache entry with mismatched certificate metadata"
+                            );
+                            continue;
+                        }
                        // fetched_at is skipped during deserialization; approximate with file mtime if available.
                        if let Ok(meta) = entry.metadata().await
                            && let Ok(modified) = meta.modified()
@@ -209,10 +403,100 @@ impl TlsFrontCache {
    }
 }

+fn cert_info_matches_domain(cached: &CachedTlsData) -> bool {
+    let Some(cert_info) = cached.cert_info.as_ref() else {
+        return true;
+    };
+    if !cert_info.san_names.is_empty() {
+        return cert_info
+            .san_names
+            .iter()
+            .any(|name| dns_name_matches_domain(name, &cached.domain));
+    }
+    cert_info
+        .subject_cn
+        .as_deref()
+        .map_or(true, |name| dns_name_matches_domain(name, &cached.domain))
+}
+
+fn dns_name_matches_domain(pattern: &str, domain: &str) -> bool {
+    let pattern = normalize_dns_name(pattern);
+    let domain = normalize_dns_name(domain);
+    if pattern == domain {
+        return true;
+    }
+
+    let Some(suffix) = pattern.strip_prefix("*.") else {
+        return false;
+    };
+    let Some(prefix) = domain.strip_suffix(suffix) else {
+        return false;
+    };
+    prefix.ends_with('.') && !prefix[..prefix.len() - 1].contains('.')
+}
+
+fn normalize_dns_name(value: &str) -> String {
+    value.trim().trim_end_matches('.').to_ascii_lowercase()
+}
+
 #[cfg(test)]
 mod tests {
    use super::*;

+    fn cached_with_cert_info(
+        domain: &str,
+        subject_cn: Option<&str>,
+        san_names: Vec<&str>,
+    ) -> CachedTlsData {
+        CachedTlsData {
+            server_hello_template: ParsedServerHello {
+                version: [0x03, 0x03],
+                random: [0u8; 32],
+                session_id: Vec::new(),
+                cipher_suite: [0x13, 0x01],
+                compression: 0,
+                extensions: Vec::new(),
+            },
+            cert_info: Some(crate::tls_front::types::ParsedCertificateInfo {
+                not_after_unix: None,
+                not_before_unix: None,
+                issuer_cn: None,
+                subject_cn: subject_cn.map(str::to_string),
+                san_names: san_names.into_iter().map(str::to_string).collect(),
+            }),
+            cert_payload: None,
+            app_data_records_sizes: vec![1024],
+            total_app_data_len: 1024,
+            behavior_profile: TlsBehaviorProfile::default(),
+            fetched_at: SystemTime::now(),
+            domain: domain.to_string(),
+        }
+    }
+
+    #[test]
+    fn cert_info_domain_match_accepts_exact_san() {
+        let cached = cached_with_cert_info("b.com", Some("a.com"), vec!["b.com"]);
+        assert!(cert_info_matches_domain(&cached));
+    }
+
+    #[test]
+    fn cert_info_domain_match_rejects_wrong_san() {
+        let cached = cached_with_cert_info("b.com", Some("b.com"), vec!["a.com"]);
+        assert!(!cert_info_matches_domain(&cached));
+    }
+
+    #[test]
+    fn cert_info_domain_match_accepts_single_label_wildcard_san() {
+        let cached = cached_with_cert_info("api.b.com", None, vec!["*.b.com"]);
+        assert!(cert_info_matches_domain(&cached));
+    }
+
+    #[test]
+    fn cert_info_domain_match_rejects_multi_label_wildcard_san() {
+        let cached = cached_with_cert_info("deep.api.b.com", None, vec!["*.b.com"]);
+        assert!(!cert_info_matches_domain(&cached));
+    }
+
    #[tokio::test]
    async fn test_take_full_cert_budget_for_ip_uses_ttl() {
        let cache = TlsFrontCache::new(&["example.com".to_string()], 1024, "tlsfront-test-cache");
@@ -230,10 +514,68 @@ mod tests {
    #[tokio::test]
    async fn test_take_full_cert_budget_for_ip_zero_ttl_always_allows_full_payload() {
        let cache = TlsFrontCache::new(&["example.com".to_string()], 1024, "tlsfront-test-cache");
-        let ip: IpAddr = "127.0.0.1".parse().expect("ip");
        let ttl = Duration::ZERO;

-        assert!(cache.take_full_cert_budget_for_ip(ip, ttl).await);
-        assert!(cache.take_full_cert_budget_for_ip(ip, ttl).await);
+        for idx in 0..100_000u32 {
+            let ip = IpAddr::V4(std::net::Ipv4Addr::new(
+                10,
+                ((idx >> 16) & 0xff) as u8,
+                ((idx >> 8) & 0xff) as u8,
+                (idx & 0xff) as u8,
+            ));
+            assert!(cache.take_full_cert_budget_for_ip(ip, ttl).await);
+        }
+
+        assert!(cache.full_cert_sent_is_empty_for_tests().await);
+    }
+
+    #[tokio::test]
+    async fn test_take_full_cert_budget_for_ip_sweeps_expired_entries_when_due() {
+        let cache = TlsFrontCache::new(&["example.com".to_string()], 1024, "tlsfront-test-cache");
+        let stale_ip: IpAddr = "127.0.0.1".parse().expect("ip");
+        let new_ip: IpAddr = "127.0.0.2".parse().expect("ip");
+        let ttl = Duration::from_secs(1);
+        let stale_seen_at = Instant::now()
+            .checked_sub(Duration::from_secs(10))
+            .unwrap_or_else(Instant::now);
+
+        cache
+            .insert_full_cert_sent_for_tests(stale_ip, stale_seen_at)
+            .await;
+        cache
+            .full_cert_sent_last_sweep_epoch_secs
+            .store(0, Ordering::Relaxed);
+
+        assert!(cache.take_full_cert_budget_for_ip(new_ip, ttl).await);
+
+        assert!(!cache.full_cert_sent_contains_for_tests(stale_ip).await);
+        assert!(cache.full_cert_sent_contains_for_tests(new_ip).await);
+    }
+
+    #[tokio::test]
+    async fn test_take_full_cert_budget_for_ip_does_not_sweep_every_call() {
+        let cache = TlsFrontCache::new(&["example.com".to_string()], 1024, "tlsfront-test-cache");
+        let stale_ip: IpAddr = "127.0.0.1".parse().expect("ip");
+        let new_ip: IpAddr = "127.0.0.2".parse().expect("ip");
+        let ttl = Duration::from_secs(1);
+        let stale_seen_at = Instant::now()
+            .checked_sub(Duration::from_secs(10))
+            .unwrap_or_else(Instant::now);
+        let now_epoch_secs = SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .unwrap_or_default()
+            .as_secs();
+
+        cache
+            .insert_full_cert_sent_for_tests(stale_ip, stale_seen_at)
+            .await;
+        cache
+            .full_cert_sent_last_sweep_epoch_secs
+            .store(now_epoch_secs, Ordering::Relaxed);
+
+        assert!(cache.take_full_cert_budget_for_ip(new_ip, ttl).await);
+
+        assert!(cache.full_cert_sent_contains_for_tests(stale_ip).await);
+        assert!(cache.full_cert_sent_contains_for_tests(new_ip).await);
    }
 }
--- a/src/tls_front/fetcher.rs
+++ b/src/tls_front/fetcher.rs
@@ -3,7 +3,9 @@
 use dashmap::DashMap;
 use std::net::SocketAddr;
 use std::sync::Arc;
+use std::sync::Mutex;
 use std::sync::OnceLock;
+use std::sync::atomic::{AtomicU64, Ordering};
 use std::time::{Duration, Instant};

 use anyhow::{Result, anyhow};
@@ -144,12 +146,37 @@ enum FetchErrorKind {
    Other,
 }

+const PROFILE_CACHE_MAX_ENTRIES: usize = 4096;
+
 static PROFILE_CACHE: OnceLock<DashMap<ProfileCacheKey, ProfileCacheValue>> = OnceLock::new();
+static PROFILE_CACHE_INSERT_GUARD: OnceLock<Mutex<()>> = OnceLock::new();
+static PROFILE_CACHE_CAP_DROPS: AtomicU64 = AtomicU64::new(0);

 fn profile_cache() -> &'static DashMap<ProfileCacheKey, ProfileCacheValue> {
    PROFILE_CACHE.get_or_init(DashMap::new)
 }

+fn profile_cache_insert_guard() -> &'static Mutex<()> {
+    PROFILE_CACHE_INSERT_GUARD.get_or_init(|| Mutex::new(()))
+}
+
+fn sweep_expired_profile_cache(ttl: Duration, now: Instant) {
+    if ttl.is_zero() {
+        return;
+    }
+    profile_cache().retain(|_, value| now.saturating_duration_since(value.updated_at) <= ttl);
+}
+
+/// Current number of adaptive TLS fetch profile-cache entries.
+pub(crate) fn profile_cache_entries_for_metrics() -> usize {
+    profile_cache().len()
+}
+
+/// Number of fresh profile-cache winners skipped because the cache was full.
+pub(crate) fn profile_cache_cap_drops_for_metrics() -> u64 {
+    PROFILE_CACHE_CAP_DROPS.load(Ordering::Relaxed)
+}
+
 fn route_hint(
    upstream: Option<&std::sync::Arc<crate::transport::UpstreamManager>>,
    unix_sock: Option<&str>,
@@ -267,6 +294,43 @@ fn remember_profile_success(
    let Some(key) = cache_key else {
        return;
    };
+    remember_profile_success_with_cap(strategy, key, profile, now, PROFILE_CACHE_MAX_ENTRIES);
+}
+
+fn remember_profile_success_with_cap(
+    strategy: &TlsFetchStrategy,
+    key: ProfileCacheKey,
+    profile: TlsFetchProfile,
+    now: Instant,
+    max_entries: usize,
+) {
+    let Ok(_guard) = profile_cache_insert_guard().lock() else {
+        PROFILE_CACHE_CAP_DROPS.fetch_add(1, Ordering::Relaxed);
+        return;
+    };
+    if max_entries == 0 {
+        PROFILE_CACHE_CAP_DROPS.fetch_add(1, Ordering::Relaxed);
+        return;
+    }
+    if profile_cache().contains_key(&key) {
+        profile_cache().insert(
+            key,
+            ProfileCacheValue {
+                profile,
+                updated_at: now,
+            },
+        );
+        return;
+    }
+    if profile_cache().len() >= max_entries {
+        // TLS fetch is control-plane work; sweeping under a tiny mutex keeps
+        // profile-cache cardinality hard-bounded without touching relay hot paths.
+        sweep_expired_profile_cache(strategy.profile_cache_ttl, now);
+    }
+    if profile_cache().len() >= max_entries {
+        PROFILE_CACHE_CAP_DROPS.fetch_add(1, Ordering::Relaxed);
+        return;
+    }
    profile_cache().insert(
        key,
        ProfileCacheValue {
--- a/src/transport/middle_proxy/mod.rs
+++ b/src/transport/middle_proxy/mod.rs
@@ -46,6 +46,7 @@ mod send_adversarial_tests;
 mod wire;

 use bytes::Bytes;
+use tokio::sync::OwnedSemaphorePermit;

 #[allow(unused_imports)]
 pub use config_updater::{
@@ -68,9 +69,32 @@ pub use secret::{fetch_proxy_secret, fetch_proxy_secret_with_upstream};
 pub(crate) use selftest::{bnd_snapshot, timeskew_snapshot, upstream_bnd_snapshots};
 pub use wire::proto_flags_for_tag;

+/// Holds D2C queued-byte capacity until a routed payload is consumed or dropped.
+pub struct RouteBytePermit {
+    _permit: OwnedSemaphorePermit,
+}
+
+impl std::fmt::Debug for RouteBytePermit {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("RouteBytePermit").finish_non_exhaustive()
+    }
+}
+
+impl RouteBytePermit {
+    pub(crate) fn new(permit: OwnedSemaphorePermit) -> Self {
+        Self { _permit: permit }
+    }
+}
+
+/// Response routed from middle proxy readers to client relay tasks.
 #[derive(Debug)]
 pub enum MeResponse {
-    Data { flags: u32, data: Bytes },
+    /// Downstream payload with its queued-byte reservation.
+    Data {
+        flags: u32,
+        data: Bytes,
+        route_permit: Option<RouteBytePermit>,
+    },
    Ack(u32),
    Close,
 }
--- a/src/transport/middle_proxy/pool.rs
+++ b/src/transport/middle_proxy/pool.rs
@@ -618,13 +618,9 @@ impl MePool {
                me_route_hybrid_max_wait: Duration::from_millis(
                    me_route_hybrid_max_wait_ms.max(50),
                ),
-                me_route_blocking_send_timeout: if me_route_blocking_send_timeout_ms == 0 {
-                    None
-                } else {
-                    Some(Duration::from_millis(
-                        me_route_blocking_send_timeout_ms.min(5_000),
-                    ))
-                },
+                me_route_blocking_send_timeout: Some(Duration::from_millis(
+                    me_route_blocking_send_timeout_ms.clamp(1, 5_000),
+                )),
                me_route_last_success_epoch_ms: AtomicU64::new(0),
                me_route_hybrid_timeout_warn_epoch_ms: AtomicU64::new(0),
                me_async_recovery_last_trigger_epoch_ms: AtomicU64::new(0),
--- a/src/transport/middle_proxy/pool_reinit.rs
+++ b/src/transport/middle_proxy/pool_reinit.rs
@@ -365,7 +365,10 @@ impl MePool {
        }
    }

-    pub async fn zero_downtime_reinit_after_map_change(self: &Arc<Self>, rng: &SecureRandom) {
+    pub async fn zero_downtime_reinit_after_map_change(
+        self: &Arc<Self>,
+        rng: &SecureRandom,
+    ) -> bool {
        let desired_by_dc = self.desired_dc_endpoints().await;
        let now_epoch_secs = Self::now_epoch_secs();
        let v4_suppressed = self.is_family_temporarily_suppressed(IpFamily::V4, now_epoch_secs);
@@ -380,7 +383,7 @@ impl MePool {
                MeDrainGateReason::CoverageQuorum
            };
            self.set_last_drain_gate(false, false, reason, now_epoch_secs);
-            return;
+            return false;
        }

        let desired_map_hash = Self::desired_map_hash(&desired_by_dc);
@@ -490,7 +493,7 @@ impl MePool {
                missing_dc = ?missing_dc,
                "ME reinit coverage below threshold; keeping stale writers"
            );
-            return;
+            return false;
        }

        if hardswap {
@@ -520,7 +523,7 @@ impl MePool {
                    missing_dc = ?fresh_missing_dc,
                    "ME hardswap pending: fresh generation DC coverage incomplete"
                );
-                return;
+                return false;
            }
        }

@@ -567,7 +570,7 @@ impl MePool {
                self.clear_pending_hardswap_state();
            }
            debug!("ME reinit cycle completed with no stale writers");
-            return;
+            return true;
        }

        let drain_timeout = self.force_close_timeout();
@@ -606,10 +609,11 @@ impl MePool {
        if hardswap {
            self.clear_pending_hardswap_state();
        }
+        true
    }

-    pub async fn zero_downtime_reinit_periodic(self: &Arc<Self>, rng: &SecureRandom) {
-        self.zero_downtime_reinit_after_map_change(rng).await;
+    pub async fn zero_downtime_reinit_periodic(self: &Arc<Self>, rng: &SecureRandom) -> bool {
+        self.zero_downtime_reinit_after_map_change(rng).await
    }
 }

--- a/src/transport/middle_proxy/reader.rs
+++ b/src/transport/middle_proxy/reader.rs
@@ -84,6 +84,7 @@ async fn route_data_with_retry(
                MeResponse::Data {
                    flags,
                    data: data.clone(),
+                    route_permit: None,
                },
                timeout_ms,
            )
@@ -639,7 +640,7 @@ mod tests {
        let routed = route_data_with_retry(&reg, conn_id, 0, Bytes::from_static(b"a"), 20).await;
        assert!(matches!(routed, RouteResult::Routed));
        match rx.recv().await {
-            Some(MeResponse::Data { flags, data }) => {
+            Some(MeResponse::Data { flags, data, .. }) => {
                assert_eq!(flags, 0);
                assert_eq!(data, Bytes::from_static(b"a"));
            }
--- a/src/transport/middle_proxy/registry.rs
+++ b/src/transport/middle_proxy/registry.rs
@@ -1,18 +1,22 @@
 use std::collections::{HashMap, HashSet};
 use std::net::SocketAddr;
+use std::sync::Arc;
 use std::sync::atomic::{AtomicU8, AtomicU64, Ordering};
 use std::time::{Duration, SystemTime, UNIX_EPOCH};

 use dashmap::DashMap;
 use tokio::sync::mpsc::error::TrySendError;
-use tokio::sync::{Mutex, mpsc};
+use tokio::sync::{Mutex, Semaphore, mpsc};

-use super::MeResponse;
 use super::codec::WriterCommand;
+use super::{MeResponse, RouteBytePermit};

 const ROUTE_BACKPRESSURE_BASE_TIMEOUT_MS: u64 = 25;
 const ROUTE_BACKPRESSURE_HIGH_TIMEOUT_MS: u64 = 120;
 const ROUTE_BACKPRESSURE_HIGH_WATERMARK_PCT: u8 = 80;
+const ROUTE_QUEUED_BYTE_PERMIT_UNIT: usize = 16 * 1024;
+const ROUTE_QUEUED_PERMITS_PER_SLOT: usize = 4;
+const ROUTE_QUEUED_MAX_FRAME_PERMITS: usize = 1024;

 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum RouteResult {
@@ -53,6 +57,7 @@ pub(super) struct WriterActivitySnapshot {

 struct RoutingTable {
    map: DashMap<u64, mpsc::Sender<MeResponse>>,
+    byte_budget: DashMap<u64, Arc<Semaphore>>,
 }

 struct WriterTable {
@@ -105,6 +110,7 @@ pub struct ConnRegistry {
    route_backpressure_base_timeout_ms: AtomicU64,
    route_backpressure_high_timeout_ms: AtomicU64,
    route_backpressure_high_watermark_pct: AtomicU8,
+    route_byte_permits_per_conn: usize,
 }

 impl ConnRegistry {
@@ -116,10 +122,23 @@ impl ConnRegistry {
    }

    pub fn with_route_channel_capacity(route_channel_capacity: usize) -> Self {
+        let route_channel_capacity = route_channel_capacity.max(1);
+        Self::with_route_limits(
+            route_channel_capacity,
+            Self::route_byte_permit_budget(route_channel_capacity),
+        )
+    }
+
+    fn with_route_limits(
+        route_channel_capacity: usize,
+        route_byte_permits_per_conn: usize,
+    ) -> Self {
        let start = rand::random::<u64>() | 1;
+        let route_channel_capacity = route_channel_capacity.max(1);
        Self {
            routing: RoutingTable {
                map: DashMap::new(),
+                byte_budget: DashMap::new(),
            },
            writers: WriterTable {
                map: DashMap::new(),
@@ -131,15 +150,30 @@ impl ConnRegistry {
                inner: Mutex::new(BindingInner::new()),
            },
            next_id: AtomicU64::new(start),
-            route_channel_capacity: route_channel_capacity.max(1),
+            route_channel_capacity,
            route_backpressure_base_timeout_ms: AtomicU64::new(ROUTE_BACKPRESSURE_BASE_TIMEOUT_MS),
            route_backpressure_high_timeout_ms: AtomicU64::new(ROUTE_BACKPRESSURE_HIGH_TIMEOUT_MS),
            route_backpressure_high_watermark_pct: AtomicU8::new(
                ROUTE_BACKPRESSURE_HIGH_WATERMARK_PCT,
            ),
+            route_byte_permits_per_conn: route_byte_permits_per_conn.max(1),
        }
    }

+    fn route_data_permits(data_len: usize) -> u32 {
+        data_len
+            .max(1)
+            .div_ceil(ROUTE_QUEUED_BYTE_PERMIT_UNIT)
+            .min(u32::MAX as usize) as u32
+    }
+
+    fn route_byte_permit_budget(route_channel_capacity: usize) -> usize {
+        route_channel_capacity
+            .saturating_mul(ROUTE_QUEUED_PERMITS_PER_SLOT)
+            .max(ROUTE_QUEUED_MAX_FRAME_PERMITS)
+            .max(1)
+    }
+
    pub fn route_channel_capacity(&self) -> usize {
        self.route_channel_capacity
    }
@@ -149,6 +183,14 @@ impl ConnRegistry {
        Self::with_route_channel_capacity(4096)
    }

+    #[cfg(test)]
+    fn with_route_byte_permits_for_tests(
+        route_channel_capacity: usize,
+        route_byte_permits_per_conn: usize,
+    ) -> Self {
+        Self::with_route_limits(route_channel_capacity, route_byte_permits_per_conn)
+    }
+
    pub fn update_route_backpressure_policy(
        &self,
        base_timeout_ms: u64,
@@ -170,6 +212,10 @@ impl ConnRegistry {
        let id = self.next_id.fetch_add(1, Ordering::Relaxed);
        let (tx, rx) = mpsc::channel(self.route_channel_capacity);
        self.routing.map.insert(id, tx);
+        self.routing.byte_budget.insert(
+            id,
+            Arc::new(Semaphore::new(self.route_byte_permits_per_conn)),
+        );
        (id, rx)
    }

@@ -186,6 +232,7 @@ impl ConnRegistry {
    /// Unregister connection, returning associated writer_id if any.
    pub async fn unregister(&self, id: u64) -> Option<u64> {
        self.routing.map.remove(&id);
+        self.routing.byte_budget.remove(&id);
        self.hot_binding.map.remove(&id);
        let mut binding = self.binding.inner.lock().await;
        binding.meta.remove(&id);
@@ -206,6 +253,64 @@ impl ConnRegistry {
        None
    }

+    async fn attach_route_byte_permit(
+        &self,
+        id: u64,
+        resp: MeResponse,
+        timeout_ms: Option<u64>,
+    ) -> std::result::Result<MeResponse, RouteResult> {
+        let MeResponse::Data {
+            flags,
+            data,
+            route_permit,
+        } = resp
+        else {
+            return Ok(resp);
+        };
+
+        if route_permit.is_some() {
+            return Ok(MeResponse::Data {
+                flags,
+                data,
+                route_permit,
+            });
+        }
+
+        let Some(semaphore) = self
+            .routing
+            .byte_budget
+            .get(&id)
+            .map(|entry| entry.value().clone())
+        else {
+            return Err(RouteResult::NoConn);
+        };
+        let permits = Self::route_data_permits(data.len());
+        let permit = match timeout_ms {
+            Some(0) => semaphore
+                .try_acquire_many_owned(permits)
+                .map_err(|_| RouteResult::QueueFullHigh)?,
+            Some(timeout_ms) => {
+                let acquire = semaphore.acquire_many_owned(permits);
+                match tokio::time::timeout(Duration::from_millis(timeout_ms.max(1)), acquire).await
+                {
+                    Ok(Ok(permit)) => permit,
+                    Ok(Err(_)) => return Err(RouteResult::ChannelClosed),
+                    Err(_) => return Err(RouteResult::QueueFullHigh),
+                }
+            }
+            None => semaphore
+                .acquire_many_owned(permits)
+                .await
+                .map_err(|_| RouteResult::ChannelClosed)?,
+        };
+
+        Ok(MeResponse::Data {
+            flags,
+            data,
+            route_permit: Some(RouteBytePermit::new(permit)),
+        })
+    }
+
    #[allow(dead_code)]
    pub async fn route(&self, id: u64, resp: MeResponse) -> RouteResult {
        let tx = self.routing.map.get(&id).map(|entry| entry.value().clone());
@@ -214,15 +319,23 @@ impl ConnRegistry {
            return RouteResult::NoConn;
        };

+        let base_timeout_ms = self
+            .route_backpressure_base_timeout_ms
+            .load(Ordering::Relaxed)
+            .max(1);
+        let resp = match self
+            .attach_route_byte_permit(id, resp, Some(base_timeout_ms))
+            .await
+        {
+            Ok(resp) => resp,
+            Err(result) => return result,
+        };
+
        match tx.try_send(resp) {
            Ok(()) => RouteResult::Routed,
            Err(TrySendError::Closed(_)) => RouteResult::ChannelClosed,
            Err(TrySendError::Full(resp)) => {
                // Absorb short bursts without dropping/closing the session immediately.
-                let base_timeout_ms = self
-                    .route_backpressure_base_timeout_ms
-                    .load(Ordering::Relaxed)
-                    .max(1);
                let high_timeout_ms = self
                    .route_backpressure_high_timeout_ms
                    .load(Ordering::Relaxed)
@@ -266,6 +379,10 @@ impl ConnRegistry {
        let Some(tx) = tx else {
            return RouteResult::NoConn;
        };
+        let resp = match self.attach_route_byte_permit(id, resp, Some(0)).await {
+            Ok(resp) => resp,
+            Err(result) => return result,
+        };

        match tx.try_send(resp) {
            Ok(()) => RouteResult::Routed,
@@ -289,6 +406,13 @@ impl ConnRegistry {
        let Some(tx) = tx else {
            return RouteResult::NoConn;
        };
+        let resp = match self
+            .attach_route_byte_permit(id, resp, Some(timeout_ms))
+            .await
+        {
+            Ok(resp) => resp,
+            Err(result) => return result,
+        };

        match tx.try_send(resp) {
            Ok(()) => RouteResult::Routed,
@@ -541,8 +665,10 @@ impl ConnRegistry {
 mod tests {
    use std::net::{IpAddr, Ipv4Addr, SocketAddr};

-    use super::ConnMeta;
-    use super::ConnRegistry;
+    use bytes::Bytes;
+
+    use super::{ConnMeta, ConnRegistry, RouteResult};
+    use crate::transport::middle_proxy::MeResponse;

    #[tokio::test]
    async fn writer_activity_snapshot_tracks_writer_and_dc_load() {
@@ -608,6 +734,55 @@ mod tests {
        assert_eq!(snapshot.active_sessions_by_target_dc.get(&4), Some(&1));
    }

+    #[tokio::test]
+    async fn route_data_is_bounded_by_byte_permits_before_channel_capacity() {
+        let registry = ConnRegistry::with_route_byte_permits_for_tests(4, 1);
+        let (conn_id, mut rx) = registry.register().await;
+        let routed = registry
+            .route_nowait(
+                conn_id,
+                MeResponse::Data {
+                    flags: 0,
+                    data: Bytes::from_static(&[0xAA]),
+                    route_permit: None,
+                },
+            )
+            .await;
+        assert!(matches!(routed, RouteResult::Routed));
+
+        let blocked = registry
+            .route_nowait(
+                conn_id,
+                MeResponse::Data {
+                    flags: 0,
+                    data: Bytes::from_static(&[0xBB]),
+                    route_permit: None,
+                },
+            )
+            .await;
+        assert!(
+            matches!(blocked, RouteResult::QueueFullHigh),
+            "byte budget must reject data before count capacity is exhausted"
+        );
+
+        drop(rx.recv().await);
+
+        let routed_after_drain = registry
+            .route_nowait(
+                conn_id,
+                MeResponse::Data {
+                    flags: 0,
+                    data: Bytes::from_static(&[0xCC]),
+                    route_permit: None,
+                },
+            )
+            .await;
+        assert!(
+            matches!(routed_after_drain, RouteResult::Routed),
+            "receiving queued data must release byte permits"
+        );
+    }
+
    #[tokio::test]
    async fn bind_writer_rebinds_conn_atomically() {
        let registry = ConnRegistry::new();
--- a/src/transport/middle_proxy/rotation.rs
+++ b/src/transport/middle_proxy/rotation.rs
@@ -47,6 +47,7 @@ pub async fn me_reinit_scheduler(
    rng: Arc<SecureRandom>,
    config_rx: watch::Receiver<Arc<ProxyConfig>>,
    mut trigger_rx: mpsc::Receiver<MeReinitTrigger>,
+    me_ready_tx: watch::Sender<u64>,
 ) {
    info!("ME reinit scheduler started");
    loop {
@@ -90,15 +91,25 @@ pub async fn me_reinit_scheduler(

        if cfg.general.me_reinit_singleflight {
            debug!(reason, "ME reinit scheduled (single-flight)");
-            pool.zero_downtime_reinit_periodic(rng.as_ref()).await;
+            if pool.zero_downtime_reinit_periodic(rng.as_ref()).await {
+                me_ready_tx.send_modify(|version| {
+                    *version = version.saturating_add(1);
+                });
+            }
        } else {
            debug!(reason, "ME reinit scheduled (concurrent mode)");
            let pool_clone = pool.clone();
            let rng_clone = rng.clone();
+            let me_ready_tx_clone = me_ready_tx.clone();
            tokio::spawn(async move {
-                pool_clone
+                if pool_clone
                    .zero_downtime_reinit_periodic(rng_clone.as_ref())
-                    .await;
+                    .await
+                {
+                    me_ready_tx_clone.send_modify(|version| {
+                        *version = version.saturating_add(1);
+                    });
+                }
            });
        }
    }
--- a/src/transport/proxy_protocol.rs
+++ b/src/transport/proxy_protocol.rs
@@ -18,6 +18,9 @@ const PROXY_V1_MIN_LEN: usize = 6;
 /// Minimum length for v2 header
 const PROXY_V2_MIN_LEN: usize = 16;

+/// Maximum accepted PROXY v2 address and TLV payload.
+const PROXY_V2_MAX_ADDR_LEN: usize = 216;
+
 /// Address families for v2
 mod address_family {
    pub const UNSPEC: u8 = 0x0;
@@ -169,6 +172,9 @@ async fn parse_v2<R: AsyncRead + Unpin>(

    let family_protocol = header[13];
    let addr_len = u16::from_be_bytes([header[14], header[15]]) as usize;
+    if addr_len > PROXY_V2_MAX_ADDR_LEN {
+        return Err(ProxyError::InvalidProxyProtocol);
+    }

    // Read address data
    let mut addr_data = vec![0u8; addr_len];
--- a/tools/grafana-dashboard.json
+++ b/tools/grafana-dashboard.json
Author	SHA1	Message	Date
Alexey	9e877e45c9	Merge pull request #788 from amirotin/feature/users-quota-endpoint Add GET /v1/users/quota endpoint	2026-05-17 11:06:06 +03:00
Mirotin Artem	0af64a4d0a	Add GET /v1/users/quota endpoint	2026-05-15 16:25:56 +03:00
Alexey	f77e9b8881	Merge pull request #783 from astronaut808/feature/user-rate-limits-api Expose user rate limits through the API	2026-05-14 18:20:04 +03:00
astronaut808	25ca64de1b	Document Docker config layout for API mutations	2026-05-13 16:42:01 +05:00
astronaut808	8895947414	Expose user rate limits through the API	2026-05-13 16:35:40 +05:00
Alexey	7a284623d6	Update API.md	2026-05-10 15:38:27 +03:00
Alexey	3bd5637e47	ME + Admission + Cleanup Correctness: merge pull request #779 from telemt/flow ME + Admission + Cleanup Correctness	2026-05-10 14:23:09 +03:00
Alexey	57b2aa0453	Rustfmt	2026-05-10 14:14:52 +03:00
Alexey	10c7cb2e0c	Middle Relay Cancellation Errors	2026-05-10 14:12:15 +03:00
Alexey	900b574fb8	Harden ME Writer Cancellation paths	2026-05-10 14:09:10 +03:00
Alexey	beed6b4679	Middle Wait Deadlines + Tighten Session Release State	2026-05-10 13:58:02 +03:00
Alexey	eef2a38c75	Type Route Cutovers + Reduce IP Tracker cleanup pressure	2026-05-10 13:55:01 +03:00
Alexey	6cb72b3b6c	Explicit Reasons of Session Fallback Cleanup + ME Close	2026-05-10 13:50:36 +03:00
Alexey	090b2ca636	Stats and Cleanup-proccess beyond Hot-path	2026-05-10 13:43:41 +03:00
Alexey	e10c070dc1	Observability + Cancellation for Middle Quota + Traffic Waits	2026-05-10 13:38:11 +03:00
Alexey	3f9ac87daf	Bounded Rate Bursts + Cancel ME Waits	2026-05-10 13:33:54 +03:00
Alexey	36de807096	Merge branch 'flow' of https://github.com/telemt/telemt into flow	2026-05-10 13:31:11 +03:00
Alexey	844a912b38	Expose Quota Contention + Cleanup fallback metrics	2026-05-10 13:30:59 +03:00
Alexey	5c5a3fae06	Update AGENTS.md	2026-05-10 13:29:02 +03:00
Alexey	ba1d9be5d4	Hardened Relays and API Security paths	2026-05-10 13:22:54 +03:00
Alexey	b2aa9b8c9e	Hardened API & Management-plane Admission - bound API and metrics connection handling - default metrics listener to localhost - reject untrusted PROXY protocol peers before parsing headers - cap API request body size and PROXY v2 payload allocation - validate route usernames and TLS domains consistently	2026-05-09 20:50:23 +03:00
Alexey	73c82bda7a	Update AGENTS.md	2026-05-09 16:34:54 +03:00
Alexey	b3510aa8b8	Bound HTTP API+Metrics Connection Admission	2026-05-09 16:29:30 +03:00
Alexey	dd3c5eff1c	Merge pull request #776 from pavlozt/fix/sudo_path Fix(installer): workaround for systems with secure PATH	2026-05-09 13:09:25 +03:00
PavelZ	dd4fb71959	Fix(installer): workaround for systems with secure PATH	2026-05-08 17:31:50 +03:00
Alexey	f0f2bc0482	Limit&Quota Saving as File + API	2026-05-08 14:38:24 +03:00
Alexey	86573be493	Event-driven Wakeup for ME Admission-gate	2026-05-08 13:34:41 +03:00
Alexey	658a565cb3	Merge pull request #770 from konstpic/feat/user-source-deny-list feat(access): add per-user source IP deny list checks	2026-05-07 11:56:54 +03:00
Alexey	29fabcb199	Merge pull request #772 from agrofx1/user_check Add root switch or login check	2026-05-07 11:53:50 +03:00
Alexey	efdf3bcc1b	Fix root detection by checking UID	2026-05-07 11:53:29 +03:00
Agrofx	66c37ad6fd	Merge branch 'flow' into user_check	2026-05-07 10:30:57 +03:00
Agrofx	0fcf67ca34	Update install.sh Co-authored-by: Dimasssss <Dimasssss2000@gmail.com>	2026-05-07 10:30:47 +03:00
Agrofx	df14762a12	Add root switch or login check	2026-05-07 06:27:51 +03:00
Alexey	4995e83236	Config Strict and Validator	2026-05-06 20:38:55 +03:00
Alexey	e0f251ad82	TLS Domains masking fixes	2026-05-06 20:29:24 +03:00
Konstantin Pichugin	b605b1ba7c	docs(access): document user_source_deny usage and API path Add config examples and behavior notes for access.user_source_deny, and clarify that it is configured through config.toml rather than dedicated user API request fields.	2026-05-06 19:17:06 +03:00
Konstantin Pichugin	b859fb95c3	feat(access): add per-user source IP deny list checks Add access.user_source_deny and enforce it in TLS and MTProto handshake paths after successful authentication to fail closed for blocked source IPs.	2026-05-06 19:11:18 +03:00
Alexey	8c303ab2b6	Merge pull request #765 from Misha20062006/patch-2 Correct saving instructions in QUICK_START_GUIDE.ru.md	2026-05-06 17:13:49 +03:00
Misha20062006	f70c2936c7	Correct saving instructions in QUICK_START_GUIDE.ru.md Updated instructions for saving changes in the guide.	2026-05-06 00:07:14 +03:00
Alexey	d67c37afd7	Merge pull request #762 from astronaut808/feature/tls-front-profile-health Add TLS Front Profile Health metrics	2026-05-05 15:23:01 +03:00
astronaut808	9f9ca9f270	Add TLS front profile health metrics	2026-05-03 18:07:24 +05:00
Alexey	cdd2239047	Merge pull request #758 from mammuthus/feature/metrics-bad-class-export-dashboard Add class-based error metrics and dashboard panels	2026-05-02 00:46:53 +03:00
Alexey	9ee341a94f	Merge pull request #757 from Dimasssss/docs Update CONFIG_PARAMS	2026-05-02 00:36:46 +03:00
mamuthus	a7a2f4ab27	Adjust General metrics dashboard layout	2026-05-01 19:19:00 +00:00
mamuthus	9dae14aa66	Add class-based error metrics and dashboard panels	2026-05-01 18:26:32 +00:00
Dimasssss	f76c847c44	Update CONFIG_PARAMS.en.md	2026-05-01 21:10:34 +03:00
Dimasssss	1aaa9c0bc6	Update CONFIG_PARAMS.ru.md	2026-05-01 21:09:38 +03:00
Alexey	e50026e776	Update README.md	2026-04-30 19:41:40 +03:00
Alexey	7106f38fae	Update Cargo.lock	2026-04-30 11:38:33 +03:00
Alexey	2a694470d5	Update Cargo.toml	2026-04-30 11:37:18 +03:00
Alexey	b98cd37211	TLS Full Certificate Budget Bookkeeping + Hot-path Cleanup and Timeout Invariants + IP-Tracker refactoring + Shard TLS Full-Cert Budget: merge pull request #753 from telemt/flow TLS Full Certificate Budget Bookkeeping + Hot-path Cleanup and Timeout Invariants + IP-Tracker refactoring + Shard TLS Full-Cert Budget	2026-04-30 11:36:30 +03:00
Alexey	8b62965978	Stabilize unknown-DC symlink race test setup	2026-04-30 11:11:04 +03:00
Alexey	d46bda9880	Preserve synchronous IP cleanup queue contract + Rustfmt	2026-04-30 11:05:18 +03:00
Alexey	c3de07db6a	Shard TLS full-cert budget tracking + Bound user-labeled metrics export cardinality	2026-04-30 11:01:10 +03:00
Alexey	61f9af7ffc	Reduce Lock-free IP-Tracker Cleanup backlog	2026-04-30 10:51:04 +03:00
Alexey	1f90e28871	Cap scanner-sensitive Caches and IP-Tracker Cardinality	2026-04-30 10:43:27 +03:00
Alexey	876b74ebf7	Hot-path Cleanup and Timeout Invariants	2026-04-29 23:16:11 +03:00
Alexey	b34e1d71ae	TLS Full Certificate Budget Bookkeeping	2026-04-29 23:00:25 +03:00
Alexey	b1c947e8e3	Limit only new ip when TimeWindow + Fix WorkingDirectory behavior + Atomically updates with Includes + Expose tls_domains links as domain-link pairs + TLS Fetcher on multiple tls_domains: merge pull request #751 from telemt/flow Limit only new ip when TimeWindow + Fix WorkingDirectory behavior + Atomically updates with Includes + Expose tls_domains links as domain-link pairs + TLS Fetcher on multiple tls_domains	2026-04-29 16:04:36 +03:00
Alexey	cfe01dced2	Bump Signed-off-by: Alexey <247128645+axkurcom@users.noreply.github.com>	2026-04-29 15:54:22 +03:00
Alexey	8520955a5f	Update helpers.rs Signed-off-by: Alexey <247128645+axkurcom@users.noreply.github.com>	2026-04-29 15:53:27 +03:00
Alexey	065786b839	TLS Fetcher on multiple tls_domains by #750 Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com> Signed-off-by: Alexey <247128645+axkurcom@users.noreply.github.com>	2026-04-29 11:47:42 +03:00
Alexey	f0e1a6cf1c	Expose tls_domains links as domain-link pairs Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com> Signed-off-by: Alexey <247128645+axkurcom@users.noreply.github.com>	2026-04-29 11:34:47 +03:00
Alexey	236bbb4970	Atomically updates with Includes Signed-off-by: Alexey <247128645+axkurcom@users.noreply.github.com>	2026-04-28 13:00:13 +03:00
Alexey	8ef5263fce	Fix WorkingDirectory behavior Signed-off-by: Alexey <247128645+axkurcom@users.noreply.github.com> Co-Authored-By: mikhailnov <m@mikhailnov.ru> Signed-off-by: Alexey <247128645+axkurcom@users.noreply.github.com>	2026-04-28 12:31:21 +03:00
Alexey	893cef22e3	Update README.md	2026-04-27 23:49:47 +03:00
Alexey	bdfa641843	Merge pull request #735 from sanekb/fix_timewindow_same_ip fix: limit only new ip when TimeWindow mode enabled	2026-04-25 19:08:36 +03:00
Alexey	007fc86189	Merge branch 'flow' into fix_timewindow_same_ip	2026-04-25 18:56:27 +03:00
Alexey	10c9bcd97d	Merge pull request #747 from telemt/flow Restore active IP observability for users without unique-IP limits	2026-04-25 18:11:30 +03:00
Alexey	8ab9405dca	Bump	2026-04-25 18:05:22 +03:00
Alexey	9412f089c0	Restore active IP observability for users without unique-IP limits	2026-04-25 15:49:28 +03:00
Alexey	4e57cee9b9	Merge pull request #745 from telemt/flow API PATCH fixes + No IP tracking with disabled unique-IP limits + Bound hot-path pressure in ME Relay and Handshake + Bounded ME Route fairness and IP-Cleanup-Backlog + Bound relay queues by bytes	2026-04-25 14:45:34 +03:00
Alexey	e217371dc8	Bump	2026-04-25 14:36:51 +03:00
sanekb	d567dfe40b	fix: limit only new ip when TimeWindow mode enabled	2026-04-25 14:36:43 +03:00
Alexey	37c916056a	Rustfmt	2026-04-25 14:35:35 +03:00
Alexey	2f2fe9d5d3	Bound relay queues by bytes Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com> Signed-off-by: Alexey <247128645+axkurcom@users.noreply.github.com>	2026-04-25 13:54:20 +03:00
Alexey	1df668144c	Bounded ME Route fairness and IP-Cleanup-Backlog Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com> Signed-off-by: Alexey <247128645+axkurcom@users.noreply.github.com>	2026-04-25 13:09:10 +03:00
Alexey	8494429690	Merge pull request #743 from amirotin/api/patch-user-null-removal feat(api): support null-removal in PATCH /v1/users/{user}	2026-04-25 13:07:13 +03:00
Alexey	f25bb17b86	Merge branch 'flow' into api/patch-user-null-removal	2026-04-25 12:28:48 +03:00
Alexey	27b5d576c0	Bound hot-path pressure in ME Relay + Handshake Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com> Signed-off-by: Alexey <247128645+axkurcom@users.noreply.github.com>	2026-04-25 12:16:26 +03:00
Alexey	e78592ef9b	Avoid IP tracking when unique-IP limits are disabled and cap beobachten memory Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com> Signed-off-by: Alexey <247128645+axkurcom@users.noreply.github.com>	2026-04-25 12:00:46 +03:00
Mirotin Artem	4ed87d1946	feat(api): support null-removal in PATCH /v1/users/{user} PatchUserRequest now uses Patch<T> for the five removable fields (user_ad_tag, max_tcp_conns, expiration_rfc3339, data_quota_bytes, max_unique_ips). Sending JSON null drops the entry from the corresponding access HashMap; sending 0 is preserved as a literal limit; omitted fields stay untouched. The handler synchronises the in-memory ip_tracker on both set and remove of max_unique_ips. A helper parse_patch_expiration mirrors parse_optional_expiration for the new three-state field. Runtime semantics are unchanged.	2026-04-25 00:49:34 +03:00
Mirotin Artem	635bea4de4	feat(api): add Patch<T> enum for JSON merge-patch semantics Introduce a three-state Patch<T> (Unchanged / Remove / Set) and a serde helper patch_field that distinguishes an omitted JSON field from an explicit null. Wired up next as the field type for the removable settings on PATCH /v1/users/{user}.	2026-04-25 00:49:34 +03:00