I have a Microsoft Exchange server and I have a RedHat server with some software on it set to relay mail out through the exchange.
The Exchange server has a receive connector set up with the internal IP of the RedHat server, yet when mail relay is attempted, nothing seems to be happening.
after a short period of time I get the error...
Mail message rejected by server - Mail server rejected recipient email address 'firstname.lastname@example.org'
If the email address that the mail is being relayed to exists on the exchange server (ie an internal mail) then delivery is successful.
Can anyone point me in the right direction for what might be blocking the delivery to external addresses for the RedHat server?