Have any of you ever heard of this...

We have machines that will all of a sudden decide that port 8080 cannot be
used on a give network segment.
move the machine to a different network segment and it will work.

Port 8080 is the transport port for our proxy....

Sometimes reseting the machines bios will clear it up sometimes reseting
the switch the machine is connected to.

Sometimes nothing seems to work. except either swapping network cards or
replacing the system(integrated NIC)

I don't even know where the issue would fall to try and get info on how to
reliably fix it.

We're running BM 38

Our network infrastructure is Cisco 6509 to 2950 switches...

This issue randomly occurs on individual machines it is not system wide.

Thank you