We have a curious issue that I need help with. We have just taken over management of an SBS 2003 server. The previous IT group set them up to use their Smarthost to route all outbound emails. Inbound MX records point to the server directly.
When I change the SMTP Connector to use DNS I see the emails entering the queues for the different domains, but they never leave.
I can telnet to port 25 of the target domains so I know port 25 is not being blocked. I also confirmed DNS is configured correctly. If I add the SMTP smarthost back into the section is clears the que and sends email out correctly.
What am I missing?