After installing the Exchange 2010 server so that it coexists with the existing exchange 2003 server, I created a test user (exch2010) and moved the mailbox to the new exchange 2010 server. So this mailbox now resides on the Exchange 2010 server. I tried sending a mail message to an existing Exchange 2003 user, and it works fine. However, when the exchange 2003 user replies it never makes it back.
Apollo = Exchange 2003 server
Ajax = Exchange 2010 server
I tried removing the existing routing group connector and recreating it via the following command:
New-RoutingGroupConnector -Name “New-Apollo-Ajax” -SourceTransportServers “ajax.fserver4.com” -TargetTransportServers “apollo.fserver4.com” -Cost 100 -Bidirectional $true -PublicFolderReferralsEnabled $true
After doing this, the problem persists. Able to send mail from Exchange 2010 to 2003, but not the other way (Exchange 2003 to 2010). Any ideas?