Update configuration.md for #185

Mentions required config changes to actually enable TFO on supported systems
varnish · Jun 23, 2020 · 8905e97 · 8905e97
1 parent b2c249d
commit 8905e97
Showing 1 changed file with 9 additions and 0 deletions.
diff --git a/docs/configuration.md b/docs/configuration.md
@@ -189,6 +189,15 @@ For supporting legacy protocol versions you may also need to lower the
 `MinProtocol` property in your OpenSSL configuration (typically
 `/etc/ssl/openssl.cnf`).
 
+## TCP Fast Open Support
+
+TCP Fast Open saves up to one full round-trip time (RTT) over 
+the standard three-way connection handshake during a TCP session.
+
+Since kernel version 3.13, the TCP Fast Open is enabled by default.
+However, it must be explcitly enabled in the configuration file:
+
+    tcp-fastopen = on
 
 ## Uninterrupted configuration reload