diff --git a/functions/info.xml b/functions/info.xml
index d30bc29baf..c79fa38ab6 100644
--- a/functions/info.xml
+++ b/functions/info.xml
@@ -206,6 +206,11 @@ $ip = getenv ("REMOTE_ADDR"); // get the ip number of the user
      specification</ulink>, specifically the <ulink
      url="&url.cgispec;">page on
      environmental variables</ulink>.
+     <note>
+      <para>
+       This function does not work in ISAPI mode.
+      </para>
+     </note>
     </para>
    </refsect1>
   </refentry>