Theres always this option: blur could block all incoming packets. you won't be able to show the send and recieve amounts but itd stop some stuff, cause from the images in this thread it looks like alot of crashing is sending packets and files to the host.

But honestly, whod waste their time to destroy a decade old game with a small community? If they really wanted to crash games they should do something more spectacular likes Halo 3 or something.