diff --git a/Changes b/Changes
index 244454a..bb06a3d 100644
--- a/Changes
+++ b/Changes
@@ -31,6 +31,9 @@
 - Fixed to put the output of the 'addendum_script' at the bottom of the email,
   and to avoid being repeated on each graph in the 'emailreports' graph.
 	(thanks to Dirk Tanneberger, os AT tanneberger.biz)
+- Fixed a wrong example in the documentation when showing how to define the same
+  port number using IPv4 and IPv6 in the 'port' graph.
+	(thanks to Dirk Tanneberger, os AT tanneberger.biz for pointing this out)
 - Small cosmetic changes.
 
 
diff --git a/man/man5/monitorix.conf.5 b/man/man5/monitorix.conf.5
index c08db64..a276b81 100644
--- a/man/man5/monitorix.conf.5
+++ b/man/man5/monitorix.conf.5
@@ -1329,11 +1329,13 @@ There is also support (Linux only) for IPv6 network ports activity by using prot
 .P
 An example would be:
 .RS
+list = 25, 25ip6, 80, 53
+.br
 <desc>
 .br
 	25 = SMTP, tcp, in/out, 0, 1000
 .br
-	25 = SMTP, tcp6, in/out, 0, 1000
+	25ip6 = SMTP, tcp6, in/out, 0, 1000
 .br
 	80 = HTTP, tcp, in, 0, 1000
 .br
@@ -1341,6 +1343,9 @@ An example would be:
 .br
 </desc>
 .RE
+.P
+As you can see, you cannot use the same port number twice. Instead, you must
+distinguish it with some suffix.
 .RE
 .P
 .BI graphs_per_row