Installed a new Exchk2k10 server, while still using and migrating away from our Exch2k3 server. I manually created the SMTP connector on the Exch2k3 server and mail was routing properly between the two servers. Now, since I ran the RU4v2 update, mail from the Exch2k10 user mailboxes get stuck in the 'Destination Unreachable' queue on Exch2k10 but outgoing externally works fine, and users on Exch2k3 continue to send outoing emails properly, even to the Exch2k10 mailboxes. Any ideas would be helpful. Config info is below:
Internet send connector has been configured with basic settings (smtp * localhost as sourceserver)
Default receive connector allowing anonymous users
Exch2k3 server has a smtp connector with the new Exck2k10 server applied as the bridgehead server
