From d9ecb662bc394cee1afe4e7d50e5056e57582296 Mon Sep 17 00:00:00 2001
From: Fujimoto Seiji <fujimoto@clear-code.com>
Date: Tue, 22 Nov 2022 15:06:31 +0900
Subject: [PATCH] in_tcp: document "send_keepalive_packet" option

See https://github.com/fluent/fluentd/pull/3961

Signed-off-by: Fujimoto Seiji <fujimoto@clear-code.com>
---
 input/tcp.md | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/input/tcp.md b/input/tcp.md
index cb1630a8..90affdd5 100644
--- a/input/tcp.md
+++ b/input/tcp.md
@@ -167,6 +167,17 @@ You can set positive value to send FIN on closing on non-Windows.
 </source>
 ```
 
+##### `send_keepalive_packet`
+
+| type | default | available transport type | version |
+| :--- | :--- | :--- | :--- |
+| bool | false | tcp, tls | 1.15.0 |
+
+Enable `SO_KEEPALIVE` on the underlying TCP sockets.
+
+This is useful when you connect to Fluentd over firewalls or proxies and
+want to prevent connections from being closed automatically.
+
 #### TLS configuration
 
 ```text