Exchange 2010 - Mail being rejected - Firwall Error

Posted on 2011-10-31
Last Modified: 2012-05-12
I'm getting random emails being rejected from different client systems it seems.

I host my own Exchange 2010 server.  FQDN

Here is a copy of the rejected email / NDR rejected your message to the following e-mail addresses:

BOYLAN MEDICAL ASSOC-BROWNING, 310 ( <> gave this error:
Firewall Error 

A problem occurred during the delivery of this message to this e-mail address. Try sending this message again. If the problem continues, please contact your helpdesk.

Diagnostic information for administrators:

Generating server: Atlas.sos.local #500 Firewall Error ##

Original message headers:

Received: from ( by ( with  Microsoft SMTP Server id 14.0.722.0; Mon, 31 Oct 2011 11:16:42 -0400
Message-ID: <20111031151642183.LCMAZmyIM80Ct0DPAlZh@atlas.sos.local>
From: Southeastern Overread Services <>
Subject: Patient Report
Reply-To: <>
Date: Mon, 31 Oct 2011 11:16:42 -0400
MIME-Version: 1.0
X-Priority: 1
X-MSMail-Priority: High
Content-Type: multipart/mixed;
Received-SPF: None (savers.sos.local: does not designate  permitted sender hosts)

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A few things that jump out at me...

1 Line 24:  It looks like my internal .local address is being used (atlas.sos.local) as my generating server.  When I check the send connected, the FQDN is listed as
2 Line 44:  The "Received-SPF" at the very bottom is listing the "savers.sos.local" as not being a designated sender...  savers.sos.local is a NLB Cluster I run on my network of 2 servers and in no way is sending out any type of email.
Question by:Brian_Huff

    Author Comment

    This has happened rarely in the past few months, but as of this morning 10/31/2011 I'm seeing a TON of them from multiple different domains we're sending to and I can't think of a single thing that has changed on our servers.

    Accepted Solution

    Ah, I have found the issue!

    The Exchange server had a second IP address assigned to it which was incorrectly listed with another server in my DNS Server

    Author Closing Comment

    Issue Found

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