We have occassionally ran into an issue after some 45+ days that our
server will slow down dramatically and within a few hours the network
cards of the BorderManager server will stop responding all together.

You can go to the server of the BorderManager server and try to ping
either the internal or external network and get no response. If you
unload the proxy services, the NIC cards will start working again. If you
reload proxy, it fails to respond. The only solution we have found is to
reboot the server.

Is there something we should be looking at?