#554 5.4.4 SMTPSEND.DNS.MxLoopback; DNS records for this domain are configured in a loop ##

Question

Hi,
This is my first post here. 
My exchange server of late is facing a peculiar problem. I get the error message that I have posted below when sending mails to any outside domain. However when I restart the server the mails can be resend to the address without any issue. After a certain
time again the issue pops up upon which I am forced to restart the server again. I am running 2007 Exchange on Windows 2003.
Generating server: name.mydomain.com
[email protected]
#554 5.4.4 SMTPSEND.DNS.MxLoopback; DNS records for this domain are configured in a loop ##
[email protected]
#554 5.4.4 SMTPSEND.DNS.MxLoopback; DNS records for this domain are configured in a loop ##
Original message headers:
Received: from name.mydomain.com ([1xx.xxx.xxx.xx5]) by MHDMAILS.mouwasat.com
 ([1xx.xxx.xxx.xx5]) with mapi; Wed, 19 Oct 2011 08:56:29 +0300
From:  <[email protected]>
To: <[email protected]>
CC: "Al Alami,Tareq" <[email protected]>
Date: Wed, 19 Oct 2011 08:56:27 +0300
Subject: RE:   
Thread-Topic:   
Thread-Index: AcyAQ5tu8z9CvBfdT5+1pcGQkk6x0AIuwczAAAGZjeABQyW5sAADeeJQAAETNDA=
Message-ID: <[email protected]>
References: <[email protected]com>
 <[email protected]com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach: yes
X-MS-TNEF-Correlator:
acceptlanguage: en-US
Content-Type: multipart/related;
            boundary="_004_EEC8FA6B3B286A4E90D709FECDF51AA06C0588CA11namedomain_";
            type="multipart/alternative"
MIME-Version: 1.0

Answer 1

On Sun, 23 Oct 2011 15:05:15 +0000, Jobin Jacob wrote:
>
>
>Even af
>
>ter removing my domain from the send connector I continue to receive the error. I would like to say I do have a firewall, Cyberoam. However, it was the same configuration till now in the firewall. I did try Mx lookup and found the following.
>
>Could there be any other solution to this issue ?
Sure, but it's necessary to ask a lot of questions since none of us
know how your organization is set up.
I see you also have "Use the External DNS Lookup settings on the
transport server" box checked. How have you configured the "External
DNS Lookups" on the HT server's property page? Is there any good
reason why you aren't just using your internal DNS servers? If the
internal DNS servers are configured to resolve (or forward) queries
for "external" domains then there's no reason to use that checkbox. In
most cases checking that box is a mistake.
http://technet.microsoft.com/en-us/library/aa997166(EXCHG.80).aspx
The behavior you describe (it works for a while and then fails;
restarting the server returns it to a working state) sure sounds like
some sort of DNS problem.
Rich Matheisen
MCSE+I, Exchange MVP
--- Rich Matheisen MCSE+I, Exchange MVP