Hello,

When I received a message from the external, I have a "loop" in my mail flow. I have not a problem with the receiving but it is strange.

My headers are the follow :

Received: from exchsrv.domain.com (192.168.1.x) by exchsrv.domain.com
 (192.168.1.x) with Microsoft SMTP Server (TLS) id 15.0.1044.25 via Mailbox
 Transport; Fri, 24 Apr 2015 13:05:07 +0200
Received: from exchsrv.domain.com (192.168.1.x) by EXCHSRV.domain.com
 (192.168.1.x) with Microsoft SMTP Server (TLS) id 15.0.1044.25; Fri, 24 Apr
 2015 13:05:07 +0200
Received: from antispam (192.168.1.x) by exchsrv.domain.com (192.168.1.x) with
 Microsoft SMTP Server id 15.0.1044.25 via Frontend Transport; Fri, 24 Apr
 2015 13:05:07 +0200

Note the uppercase in the second receive.

I do not really understand when the problem could be.

Thanks

Internet -> Antispam -> Exchange Front End Transport (CAS) -> Exchange Transport (MBX) -> (... Mailbox)

Both Front End and Back End stamp the header with their routing component.

Hi ,

Did you get NDR  for message looping ? or else you have taken the above trace from the message headers of the received email.

If that the above headers was taken from the delivered email then it was not looping and it is an normal behavior in exchange message routing process.