I recently installed Exchange 2010 into my Exchange 2003 organization and, sadly, am unable to send mail internally.
The installation completed successfully, and I can send and receive external mail with mailboxes on each server, but I am not able to send mail from a mailbox on the 2003 server to a mailbox on the 2010 server, and vice versa. I can send mail to other mailboxes within the same server.
When looking at the queue on the 2010 server the message says "451 4.4.0 Primary target IP address responded with: "451 5.7.3 Cannot achieve Exchange Server authentication."”
On the 2003 server, I watch the mail go into the routing group connector queue, and then it ends up in the “Messages with an unreachable destination” queue.
My MX record is the 2003 server, so somehow mail does make it from the 2003 server to the 2010 server if it comes in externally.
I am running anti-spam software (MailMarshal) on each server that sits in front of Exchange and listens on port 25 as the smart host.
On the 2003 server, the SMTP protocol default SMTP virtual server is set to use port 26, and the routing group connector is set to use the smart host.
On the 2010 server, the receive connector is configured to use port 26, and the send connector is set to use the smart host.
Both servers have the routing group connector that was created at installation and each have the appropriate remote bridghead configuration.
External mail is received by the smart host on the 2003 server and is then routed to Exchange, where it ultimately makes it to mailboxes on the 2003 or the 2010 server. It is just failing when I try to send internally between these servers.
Not sure if this helps, but when I view the staus on the 2003 server, everything shows available, except the 2010 server itself. The connectors from the 2010 server do display and show as available, however.
I suspect this requires some sort of routing connector, or something, but I am staring at a brick wall right now.
Does anyone have advice on where I should begin, please?
Thanks in advance for your generous assistance!