From 9b816171ac2407246d5cef0e1bb9670f4bb4cfbc Mon Sep 17 00:00:00 2001
From: Arnold Zokas <arnold.zokas@coderoom.net>
Date: Tue, 20 Apr 2021 15:28:34 +0100
Subject: [PATCH] doc: document new TCP_KEEPCNT and TCP_KEEPINTVL socket option
 defaults

PR https://github.com/nodejs/node/pull/32204 introduced new defaults for the TCP keep-alive socket options (see deps/uv/src/unix/tcp.c):
- "TCP_KEEPCNT" now defaults to 10 on all platforms
- "TCP_KEEPINTVL" now defaults to 1 on all platforms

Previously, "TCP_KEEPCNT" and "TCP_KEEPINTVL" were not set explicitly and OS-default values were used.

Fixes: https://github.com/nodejs/node/issues/38298
Refs: https://github.com/nodejs/node/pull/32204
---
 doc/api/net.md | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/doc/api/net.md b/doc/api/net.md
index 699b1ba4d573b8..17ef5c9d0cb9d6 100644
--- a/doc/api/net.md
+++ b/doc/api/net.md
@@ -1006,6 +1006,10 @@ Set the encoding for the socket as a [Readable Stream][]. See
 ### `socket.setKeepAlive([enable][, initialDelay])`
 <!-- YAML
 added: v0.1.92
+changes:
+  - version: v12.17.0
+    pr-url: https://github.com/nodejs/node/pull/32204
+    description: New defaults for `TCP_KEEPCNT` and `TCP_KEEPINTVL` socket options were added.
 -->
 
 * `enable` {boolean} **Default:** `false`
@@ -1020,6 +1024,12 @@ data packet received and the first keepalive probe. Setting `0` for
 `initialDelay` will leave the value unchanged from the default
 (or previous) setting.
 
+Enabling the keep-alive functionality will set the following socket options:
+- `SO_KEEPALIVE=1`
+- `TCP_KEEPIDLE=initialDelay`
+- `TCP_KEEPCNT=10`
+- `TCP_KEEPINTVL=1`
+
 ### `socket.setNoDelay([noDelay])`
 <!-- YAML
 added: v0.1.90