We have recently decided to change our internet service provider and are having trouble getting outbound e-mail to work correctly. We started by changing our mx records in our domain registers DNS record to point it to our new router IP address. After that we changed our servers gateway addresses to the internal IP address for the new router. After about 2 hours email started coming into our Exchange Server and of course our internet had been working all along, however outgoing mail continued to sit in the queue on the mail server. We know that the DNS on the exchange server points to our Domain controller and that the forwarders on the domain controller have our ISP’s DNS servers in it, and that the router is allowing outbound traffic on port 25. Can anyone think of anything else that would need to be changed or why this might be happening?