I'm try to replace a W2K EMail Server with a W2K3 Email Server because the 1st server is receiving a message to the effect that the disk is failing. My problem is that he W2K3 server will only run for a couple of hours before refusing to receive transmissions FROM the internet. At that point I cannot telnet to the server for either port 25, 110, or 3389. I can, from the computer, connect to internet web sites. The computer is a dual homed machine that belongs to a local domain. The W2K3 server is set up to be as identical as possible to the W2K server.
In process, here's what I'm doing. I rename the old mail server and then shut it down. I rename the new mail server to the orignal name of the old mail server and shut it down. I unplug the W2K box from the Linksys router that connects our system to our DSL supplier. I connect the W2K3 box to the same port on the router that the W2K server was connected to (the two boxes have the same hardwired ipaddresses). I restart the W2K3 computer. WAN computers can see the new box and can telnet to the smtp port. Wan computers can also connect to the box for admin access via RDP. This all works for about an hour or two. At that point, everything fails. Outside systems can no longer telnet in on port 25 or 3389. The mail server software is still operational, one can connect to it on the local LAN. And, it seems to be able to send mail to the outside world. However, the outside world cannot connect to it. I had to shut down the new mail server and restart the old one. After a renaming operation, all is well ... but the disk is still reporting that failure is imminent. The router seems to work with the W2K server, but has problems with the W2K3 server.
The server is W2K3 SP1. I do have a Terminal Server that will only work if I remove the SP1 upgrade. I'd do that on the mail server, but SP1 was built into the install.