MS decided to use only reliable packets?

Not sure what the issue is, but it has to do with Checksum offloading and is apparently only a problem with 2008. Disabling checksum offloading on the NIC fixes the problem, but it took forever to come up with

that fix. We were having problems with programs that need to talk to a license server on campus not working over a Cisco VPN. Only affected a program that used UDP to talk to the server, and only over VPN.

Really looked like a firewall issue, but after lots of network captures it turned out that the server was dropping the UDP responses.

Thanks a lot Microsoft.