diff --git a/docs/configuration_file_basics.xml b/docs/configuration_file_basics.xml
index 0b7eb556b..451a8d953 100644
--- a/docs/configuration_file_basics.xml
+++ b/docs/configuration_file_basics.xml
@@ -346,12 +346,14 @@ smtp,www,pop3,imap  #Services running on the firewall</programlisting>
   <section id="INCLUDE">
     <title>INCLUDE Directive</title>
 
-    <para>Any file may contain INCLUDE directives. An INCLUDE directive
-    consists of the word INCLUDE followed by a path name and causes the
-    contents of the named file to be logically included into the file
-    containing the INCLUDE. Relative path names given in an INCLUDE directive
-    are assumed to reside in /etc/shorewall or in an alternate configuration
-    directory if one has been specified for the command.</para>
+    <para>Any configuration file may contain INCLUDE directives (INCLUDE is
+    not supported in <ulink url="shorewall_extension_scripts.htm">extension
+    scripts</ulink>). An INCLUDE directive consists of the word INCLUDE
+    followed by a path name and causes the contents of the named file to be
+    logically included into the file containing the INCLUDE. Relative path
+    names given in an INCLUDE directive are assumed to reside in
+    /etc/shorewall or in an alternate configuration directory if one has been
+    specified for the command.</para>
 
     <para>INCLUDE's may be nested to a level of 3 -- further nested INCLUDE
     directives are ignored with a warning message.</para>