Carlos, check the mail logs of your web-server, your domain might have a primary A-record pointing to something different than MX-records. When the MX servers do something like greylisting and bounce with a temp-code (4xx) hotmail servers will try alternative records (like @ IN A) and might find a listening mail-daemon at your webserver. At 23-10-2012 00:16, Carlos M. Perez wrote:
Hi,
We're trying to resolve some delivery issues reported by hotmail users. Started happening a few weeks ago. Getting immediate NDRs, and the server that is supposed to receive the email has no records of attempts. The messages also don't match what the receiving server should be sending. The server(s) listed in the MX should receive all email without authentication, since it's a mail filtering service (Maxmail)
= Reporting-MTA: dns;snt0-omc3-s27.snt0.hotmail.com Received-From-MTA: dns;SNT133-W53 Arrival-Date: Mon, 22 Oct 2012 14:09:49 -0700
Final-Recipient: rfc822;administrator@xxxx.com Action: failed Status: 5.5.0 Diagnostic-Code: smtp;550 authentication required =
Kindly contact me off-list.
Thanks,