I'm in the process of upgrading an Exchange 2003 server to Exchange 2010, and have installed the prerequisites and Exchange 2010 on the new hardware I've purchased.
We use postfix on the perimeter to handle external SMTP connections, and Exchange 2003 is configured to send all external mail via the same postfix instance.
The Exchange 2010 server is now up and running, and I've just performed a mailbox move for a test account to the new server. The mailbox move was flawless, with the client picking up the new server without any problem.
I've then sent an email from the test account (now on Ex 2010) to my own mailbox (still on Ex 2003), which worked fine, but when I reply to the test account, our Exchange 2003 server is attempting to route the message via our postfix instance, instead of routing it to the new Exchange 2010 server.
What might I be missing?
For info, the Exchange 2010 server is installed with the 'typical' roles, as it will be a single server (I intend to keep postfix on the perimeter).
Edit - Output from Get-RoutingGroupConnector executed on the Exchange 2010 server
[PS] C:\Windows\system32>Get-RoutingGroupConnector Name SourceRoutingGroup TargetRoutingGroup ---- ------------------ ------------------ EX2010-EX2003 Exchange Routing Group (DWBGZMFD01QNBJR) first routing group EX2003-EX2010 first routing group Exchange Routing Group (DWBGZMFD01QNBJR)