I have a problem with a customer of mine. Everything was working
perfectly. Then, last night, they did two things: 1) They installed
Microsoft Exchange on the server, and 2) They installed the "Recommended
Security Update" from Microsoft Windows Update (This is Windows 2000
Server). Now, this morning, their server is refusing all incoming
connections into Firebird. None of his client computers can
connect. They're getting the infamous message that it can't establish a
connection because "the server actively refused it".

I've checked the things that I know to check. The network connection is
not firewalled, the correct Services entry is there. They didn't install
any new security programs, and didn't change any networking hardware.

Does anyone know what the problem could be?

-Joe