diff --git a/doc/guide.tex b/doc/guide.tex
index d77a2525f..b2034f2b4 100644
--- a/doc/guide.tex
+++ b/doc/guide.tex
@@ -2083,7 +2083,7 @@ listen:
     port: 3478
     transport: udp
     use_turn: true
-    turn_ip: 10.20.30.1
+    turn_ip: "10.20.30.1"
     module: ejabberd_stun
   ...
 \end{verbatim}