Mail loop

[Sebastian Albrink]

Hi list,

I am having a problem with mail loops :-(

Whenever I set one of my non-kolab email accounts to forward its mails  
to my kolab3 email address, Kolab3 receives the mail, passes it  
through amavis and sends it back to the original "to" address. From  
there it is send back to kolab, the looping starts :-/

Attached you'll find the mail header with an example.

Any suggestions?

Regards,
Sebastian

-------------- next part --------------
This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its recipients. The following addresses failed:

  <original_address at some-provider.net>

SMTP error from remote server after transfer of mail text:
host mail.exchange.server [567.890.123.456]:
550 Loop detected


--- The header of the original message is following. ---

Received: from my.kolab.server (... [my.ip.add.ress])
        by mail.relay.server (node=mrbap2) with ESMTP (Nemesis)
        id 0Ll0b7-1T80mI1nJl-00aXLh; Tue, 11 Dec 2012 21:43:35 +0100
Received: from my.kolabserver.domain (localhost [127.0.0.1])
        by my.kolab.server (Postfix) with ESMTP id DB84F3FF7D
        for <original_address at some-provider.net>; Tue, 11 Dec 2012 21:43:32 +0100 (CET)
Received: from localhost (localhost [127.0.0.1])
        by my.kolab.server (Postfix) with ESMTP id 27BC53FF7D
        for <forward_to_address at my-kolab-installation.net>;
        Tue, 11 Dec 2012 21:43:32 +0100 (CET)
X-Virus-Scanned: amavisd-new at my.kolabserver.domain
X-Spam-Flag: NO
X-Spam-Score: 0
X-Spam-Level:
X-Spam-Status: No, score=0 tagged_above=-10 required=6.2
        tests=[HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001,
        SPF_HELO_PASS=-0.001] autolearn=ham
Received: from my.kolab.server ([127.0.0.1])
        by localhost (my.kolab.server [127.0.0.1]) (amavisd-new, port 10024)
        with ESMTP id FaHcj4jrTE7v for <forward_to_address at my-kolab-installation.net>;
        Tue, 11 Dec 2012 21:43:28 +0100 (CET)
Received: from mailserver.some-provider.net (mailserver.some-provider.net [123.123.123.123])
        by my.kolab.server (Postfix) with ESMTP id 7B2FC3FF5A
        for <forward_to_address at my-kolab-installation.net>;
        Tue, 11 Dec 2012 21:43:26 +0100 (CET)
Received: from sending.mail.server ([80.149.113.205])
        by mx.some-provider.net (node=mxeu5) with ESMTP (Nemesis)
        id 0MhDCX-1TUtLS1z5l-00Mxny for original_address at some-provider.net;
        Tue, 11 Dec 2012 21:43:27 +0100

From: <someone at example.org>
To: <original_address at some-provider.net>
Date: Tue, 11 Dec 2012 21:43:27 +0100
Subject: test
[..]