There’s nothing worse than a server that seems to be behaving itself when you are at the console, but from remote it’s just dicking about. One of my Hyper-V nodes decided to start playing the packet loss game for absolutely no reason. It had recently been the victim of a fail-over when the other node fell down but other than that, there was no reason for it.
Sitting on the node and pinging out, everything seemed to look fine. Browsing the network was fine, everything was good. Contacting the node however, packet loss, rdp hanging, etc.
Annoyingly, the fix was simple yet stupid since the nodes are set up identically. In the advanced tab of the network card, TCP offloading needed to be disabled. That simple. Once set, it behaved correctly again with no issues.