diff --git a/TCP-Fast-Open.md b/TCP-Fast-Open.md
index a1cc167..9fe0523 100644
--- a/TCP-Fast-Open.md
+++ b/TCP-Fast-Open.md
@@ -1,8 +1,10 @@
 If both of your server and client are deployed on Linux 3.7+, you can turn on
 fast_open for lower latency.
 
-Turn on fast open:
+Turn on fast open temporarily:
 
     echo 3 > /proc/sys/net/ipv4/tcp_fastopen
 
-Then set fast_open to true in your config.json.
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+Then set fast_open to true in your config.json.
+
+To turn on fast open permanently, see [Optimizing Shadowsocks](https://github.com/clowwindy/shadowsocks/wiki/Optimizing-Shadowsocks).
\ No newline at end of file