From c86dc2f65e62b740568d230ea5cbcfcde84e042e Mon Sep 17 00:00:00 2001
From: Alexey <247128645+axkurcom@users.noreply.github.com>
Date: Thu, 11 Jun 2026 23:59:47 +0300
Subject: [PATCH] Docs for SYN Limiter

Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com>
---
 docs/Config_params/CONFIG_PARAMS.en.md | 17 +++++++++++++++++
 docs/Config_params/CONFIG_PARAMS.ru.md | 17 +++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/docs/Config_params/CONFIG_PARAMS.en.md b/docs/Config_params/CONFIG_PARAMS.en.md
index 8fcb7d8..3268996 100644
--- a/docs/Config_params/CONFIG_PARAMS.en.md
+++ b/docs/Config_params/CONFIG_PARAMS.en.md
@@ -2219,6 +2219,7 @@ Note: This section also accepts the legacy alias `[server.admin_api]` (same sche
 | [`ip`](#ip) | `IpAddr` | — | `✘` |
 | [`port`](#port-serverlisteners) | `u16` | `server.port` | `✘` |
 | [`client_mss`](#client_mss-serverlisteners) | `String` | `[server].client_mss` | `✘` |
+| [`synlimit`](#synlimit-serverlisteners) | `false`, `"iptables"`, or `"nftables"` | `false` | `✘` |
 | [`announce`](#announce) | `String` | — | `✘` |
 | [`announce_ip`](#announce_ip) | `IpAddr` | — | `✘` |
 | [`proxy_protocol`](#proxy_protocol) | `bool` | — | `✘` |
@@ -2254,6 +2255,22 @@ Note: This section also accepts the legacy alias `[server.admin_api]` (same sche
     port = 443
     client_mss = "256"
     ```
+## synlimit (server.listeners)
+  - **Constraints / validation**: `false`, `"iptables"`, or `"nftables"`. Omitted or `false` disables SYN limiting for this listener.
+  - **Description**: Installs per-listener Linux netfilter SYN limiter rules for the listener port. `"iptables"` uses `iptables`/`ip6tables` filter rules with the `recent` match name `telemt`. `"nftables"` uses nftables dynamic timeout sets and auto-detects whether the host already uses `inet`, `ip`, or `ip6` table families before creating Telemt-owned tables. Rules are reconciled at runtime and removed during graceful Telemt shutdown; `SIGKILL` cannot be cleaned up by the process. Requires CAP_NET_ADMIN and listener restart/rebind for config changes.
+  - **Example**:
+
+    ```toml
+    [[server.listeners]]
+    ip = "0.0.0.0"
+    port = 443
+    synlimit = "iptables"
+
+    [[server.listeners]]
+    ip = "::"
+    port = 443
+    synlimit = "nftables"
+    ```
 ## announce
   - **Constraints / validation**: `String` (optional). Must not be empty when set.
   - **Description**: Public IP/domain announced in proxy links for this listener. Takes precedence over `announce_ip`.
diff --git a/docs/Config_params/CONFIG_PARAMS.ru.md b/docs/Config_params/CONFIG_PARAMS.ru.md
index 7d473d8..02d336b 100644
--- a/docs/Config_params/CONFIG_PARAMS.ru.md
+++ b/docs/Config_params/CONFIG_PARAMS.ru.md
@@ -2225,6 +2225,7 @@
 | [`ip`](#ip) | `IpAddr` | — | `✘` |
 | [`port`](#port-serverlisteners) | `u16` | `server.port` | `✘` |
 | [`client_mss`](#client_mss-serverlisteners) | `String` | `[server].client_mss` | `✘` |
+| [`synlimit`](#synlimit-serverlisteners) | `false`, `"iptables"` или `"nftables"` | `false` | `✘` |
 | [`announce`](#announce) | `String` | — | `✘` |
 | [`announce_ip`](#announce_ip) | `IpAddr` | — | `✘` |
 | [`proxy_protocol`](#proxy_protocol) | `bool` | — | `✘` |
@@ -2260,6 +2261,22 @@
     port = 443
     client_mss = "256"
     ```
+## synlimit (server.listeners)
+  - **Ограничения / валидация**: `false`, `"iptables"` или `"nftables"`. Если параметр не задан или задан как `false`, SYN limiter для этого listener’а выключен.
+  - **Описание**: Устанавливает per-listener Linux netfilter SYN limiter rules для порта listener’а. `"iptables"` использует `iptables`/`ip6tables` filter rules с `recent` name `telemt`. `"nftables"` использует nftables dynamic timeout sets и автоматически определяет, какие table families уже используются на хосте (`inet`, `ip`, `ip6`), перед созданием Telemt-owned tables. Rules reconciled at runtime и удаляются при graceful shutdown Telemt; `SIGKILL` процессом не очищается. Требует CAP_NET_ADMIN и restart/rebind listener’а для изменений конфигурации.
+  - **Пример**:
+
+    ```toml
+    [[server.listeners]]
+    ip = "0.0.0.0"
+    port = 443
+    synlimit = "iptables"
+
+    [[server.listeners]]
+    ip = "::"
+    port = 443
+    synlimit = "nftables"
+    ```
 ## announce
   - **Ограничения / валидация**: `String` (необязательный параметр). Не должен быть пустым, если задан.
   - **Описание**: Публичный IP-адрес или домен, объявляемый в proxy-ссылках для данного listener’а. Имеет приоритет над `announce_ip`.