Detecting packet injection: a guide to observing packet spoofing by ISPs

Handy little guide to see if your ISP is packet spoofing you, AKA making BitTorrent or gnutella or whatever not work. It does take a bit of understanding how teh intarweb works, but ya'll are smart and stuff. so here ya go:

http://www.eff.org/wp/detecting-packet-injection