OK, here is the latest crazy problem...
Over the past few weeks our Exchange Server has been getting bogged down with SMTP connections, it seems that they are connecting and doing what they have to but it's just taking forever, so the connections are getting to the MAX of 100 that we have set! Slowly but surly they clear up and the connection count returns to normal. While this is happening you can telnet to port 25 and you can see everything just seems to be moving slowly. We have the diagnostics logging turned on and it rarely shows that any of the connection are timing out. We are also looking and comparing the inbound connections to see if it is a particular server's) causing the problem. There have been no correlations thus far!
It's your typical Exchange 5.5 with IMC running, we also use Antigen v6, it's also being ported through ISA server.
Sometimes it goes for days and everything is fine, then all of the sudden the connections just keep building. If we don't try to fix it by rebooting or stopping the IMC everything usually just works itself out in about an hour.
The machine is regularly defragged, nothing else running on it, and it is a dual Xeon with 2GB of RAM... I'm at a loss...
It's running a Intel Pro Copper Gigabit card at 1Gb as well.
During the phenomena the CPU is almost idle, and the Hard Drives are chugging, but not extensively?!
Any input would be greatly appreciated!