Details:Brand new SBS 2003 Install, all service packs and updates applied, CEICW run with no errors and properly setup. Built a new server to replace a very old workhorse and am using that as a baseline in order to make certain all of my settings are correct. IPConfig shows up with the correct info, there are no other problems with the new installation.Problem:Sending and Receiving mail works locally, and sending mail externally works. Receiving mail from an external server, however, does not. Using SMTP Connector.Attempted Solutions:MX Record is correct, that was the first thing I checked. Points to my router which forwards to the server's IP.Telnet into the server works flawlessly, can send and receive from both a computer ON the network and OFF the network, as well as locally (from the server.)IPConfig reports all correct information, have compared to the old server as well, and all the information is identical.All settings within all portions of Exchange Setup are identical between old and new server, the old server worked FLAWLESSLY for the past... geez... 5 years.. and continues to work flawlessly as soon as I unplug the new server and put the old one back on the network.By my reckoning, this should be working, but it's not.The *ONLY* change I have made that is "different" from the old server is changing internal IP addresses from 192.168.1.7 to 192.168.1.9 - However, this should not cause a problem (correct?) as long as I have the ports forwarded to the new internal IP - correct? Since the MX record points to the router IP, it should be up to the router as to where those packets get sent in the end.Any suggestions on my next move? I'm starting to get pretty frustrated here. If anyone wants to see any logs or anything, just let me know which ones.Thanks,Jake

You should check if you can connect to your server specified in the MX record on port 25 from the internet So run this from a computer from on the internet TELNET server.domain.com 25 Deli

You may want to check the Firewall settings in SBS as well. By default port 25 is closed on 2003 Server R2. (It may be closed on earlier releases as well.) Add an exception in the list for port 25 TCP and see if that helps.