Exchange 2010 to Exchange 2003 Mail Routing

Having trouble with a basic Exchange migration from SBS 2003 to Exchange 2010 running under Server 2008 R2.

Everything's installed.  I can send mail in all directions from both servers, EXCEPT I can't send from 2010 to 2003.  Messages sit in Exchange 2010 Server queue for unreachable domain.

I have created (then deleted and recreated) a pair of Routing Groups to go between the two servers.

Both servers have been restarted multiple times.

I've compared the routing groups, the SEND connectors and the RECEIVE connectors to other servers I've built and them match identically, but can't get mail to pass.

I've checked the 2003 Server to confirm that it's not routing all outbound mail to a smarthost, it's using DNS to directly route mail.  I read in a few posts that could present an issue.

Any help would be appreciated!


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Will SzymkowskiSenior Solution ArchitectCommented:
Have you checked the logs on both server to see where the issue might be located? If you are in fact having routing issues you should see warning or errors in the Applicaiton/Exchange logs stating this. These logs will provide more detail on where communication is being lost.

Simon Butler (Sembee)ConsultantCommented:
Check there are not restrictions on the SMTP virtual server that will stop the traffic flowing.
Also ensure that the FQDN on the SMTP virtual server resolves internally correctly.
Can you telnet to port 25 of the Exchange 2003 server from the 2010 server? Use netbios name, fqdn and IP address.


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NEMCAuthor Commented:
Thanks for the replies.

Simon, I am able to telnet 25 to all of the relevant name, and there are no restrictions on the SMTP Virtual Server.

Will, there are no messages in the Event Logs relative to mail routing.  I assume the logging level is set too low.  I will poke around and see I can locate verbose mode.
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