Split domain - A configuration error in the e-mail system caused the message to bounce between two servers or to be forwarded between two recipients

Hi all

I'm currently transitioning from Exchange 2003 to Exchange 2010 but my split domain/namespace has stopped working - although it took a week to stop!

We have a namespace which was split between two Exchange 2003 servers in separate Admin groups - one in UK, one in Australia.  We then had a  connector routing this specific domain between these two servers.  All was working OK.

We have now installed an Exchange 2010 server into the UK Admin group and initially all was OK.  However, the split domain changed itself (at least I'm not aware of a manual change) from Authoritative to Internal Relay domain.  This resulted in NDRs being generated when sending into this domain from external sources (UK only - Aus was still receiving OK).

We changed this back to Authoritative and external mail now being received.  But when I send an e-mail to this domain for an Australian recipient from a mailbox on my Exchange 2003 server I get "A configuration error in the e-mail system caused the message to bounce between two servers or to be forwarded between two recipients.  Contact your administrator." error message.

If I send it from a mailbox on my Exchange 2010 server then it's delivered OK.

I've tried removing my UK Exchange 2003 connector.
I've tried pointing the Smart Host for this connector to my Exchange 2010 server
I've tried setting up a separate SMTP Virtual Server on my UK Exchange 2003 server

All of which result in the same error message.

Message tracking indicates that it's not leaving my UK Exch2003 server and generating the NDR from there.

I can't really find any config guides about split domain involving 3 servers or from transitioning a split domain from 2003 to 2010.

All e-mails from Aus to UK (Exch2003 & 2010) are received OK.

Any ideas?


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Simon Butler (Sembee)ConsultantCommented:
Your use of the term split domain isn't standard, so you will have to clarify something.

Are all of the Exchange servers in the same AD Forest?
If not, then what is the relationship between the sites?

When you deploy Exchange 2010 for the first time, it creates a routing group connector between Exchange 2003 and 2010. It isn't unusual for that process to not work correctly and the RGC needs to be recreated.
Furthermore, you can add in additional RGCs between Exchange 2010 and other Exchange 2003 servers, to reduce the hops. That needs to be done from Exchange 2010 using new-routinggroupconnector.

I would also check your RUS settings carefully. Ensure that RUS is being used for just email domains. If you have a mailbox manager policy as well, then create a new policy for that and remove mailbox manager from the RUS that has the list of accepted domains.

TTG-GroupAuthor Commented:
Hi Simon

Thanks for getting back to me so quickly.

We've sorted it now.  We cleaned up the mailflow between the two servers and forced all UK Exch2003 mails via the UK Exch2010 server (rather than the other way round).

The "Internal Relay" accepted domain then behaved as expected.


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TTG-GroupAuthor Commented:
Forcing all mails through Exchange 2010 rather than continuing to use Exch2003 for mailflow ensured that the "Internal Relay" accepted domain type allowed the proper functionality to split a namespace across two separate Exchange servers.
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