554 5.4.4 SMTPSEND.DNS.MxLoopback Error for multiple email domained site.

Posted on 2013-11-24
Medium Priority
Last Modified: 2013-12-18
I'm in the process of merging an office with SBS2003 with one with SBS2008. The SBS2003 device has been decomissioned and the data and users have been sucessfully moved to the SBS2008 machine.

The old SBS2003 users still wish to use their old email addresses so I've set up Exchange 2007 on the SBS 2008 box with multiple email domains and this is working fine for sending emails to or from external email addresses.

However they get

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

when attempting to send an email from the new email address to the existing one.

Unfortunatley to complicate things further, the sbs2008 companies MX record points to a third party email provider and the existing users are using POP3 to collect the emails from there (I know, I know).

The obvious fix is to dump the third party email provider and move everything onsite but the users are particualarly computer phobic and some of them including the director are extremly resistant to changing the setup they have and wants me to 'leave things as they are' for the original SBS2008 users.

So the details...
Company 1: Office closing down and users being moved to Company 2's offices.
Lets call them  users@company1.com
Used Outlook 2007 and Exchange 2003 for emails

Company 2:
Lets call them  users@company2.com
Uses Incredimail with POP3 for their emails. Uses Incredimal Email app.
SBS 2008 setup with POP3 connectors to collect the mail
Sending currently using DNS and not a smarthost for sending.

I've added the users of Company1 to the SBS2008 box and configured the users to send and receive via DNS using user@Company1.com email address.

People from Company2 can still send and receive from their accounts, including to company1.com
People from Company1 can now send/receive emails using their user@company1.com email address on Company2's server but cannot send to Company2.com due to MxLoopback Error.

Are there any additional setting I need to do to make this work?

On company2's SBS2008 server I've...

Gone into EMC >> Org Conf >> Hub Transport >> Accepted Domain and added the Company1.com Email domain as an 'authoritive'. Company2.com is currently set to 'External Relay' due to POP 3 connectors maybe???
The default authoritive setting is company2.local

In EMC >> Org Conf >> Hub Transport >> Email Address Policies, the 'SBS Email Address Policy'has Priotiy 1, the Company1.com entry is at Priority 2
They're both current using default settings for the policies themselves.

In EMC >> Recipient Configuration, the new users with Company1.com email addresses have had their user@company1.com entry 'Set as Reply'
In EMc >> Recipeint Configuration, the exisiting users with Company2.com emails addresses have had their user@company2.com entry 'Set as Reply'

Is there anything else I need to do?
Question by:Dale303

Accepted Solution

donnk earned 2000 total points
ID: 39672632
you need to set the sbs box to be non-authoritive for company 2 as the pop host is the mail server not your sbs box


Author Comment

ID: 39677475
Yeah, that's how it was set up already. I think I've cracked it though. These were/are the Accepted Domains settings..

Company1.com, Authoritive, Default:False
Company2.com, External Relay, Default:False
Company1.local, Authoritive, Default:True

E-mail Address Policies was set like this...

Company1.com, Priority:1, Applied:True
Company2.com, Priority:2, Applied:True
Default Policy, Priority:Lowest, Applied:True

Those didn't work. Changing them to this...

Company2.com, Priority:1, Applied:True
Company1.com, Priority:2, Applied:True
Default Policy, Priority:Lowest, Applied:True

didn't work either, but

Company1.com, Priority:1, Applied:True
Default Policy, Priority:Lowest, Applied:True

Seems to have fixed things.

I'm still wondering why swapping the priority order didn't work but hey.

Thanks for your help.

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