diff --git a/docs/6to4.xml b/docs/6to4.xml
index 8852e93d8..2edd3c29f 100644
--- a/docs/6to4.xml
+++ b/docs/6to4.xml
@@ -464,7 +464,8 @@ dmz	        ipv6</programlisting></para>
       <para><filename>/etc/shorewall6/interfaces</filename>:</para>
 
       <blockquote>
-        <para><programlisting>#ZONE           INTERFACE               OPTIONS
+        <para><programlisting>?FORMAT 2
+#ZONE           INTERFACE               OPTIONS
 
 net             sit1                    tcpflags,forward=1,nosmurfs
 loc             eth0                    tcpflags,forward=1