But when you try to run a Gnutella P2P node on your machine, things start getting strange. Gnutella operates in two stages: first of all, your node starts a conversation with other nodes on the network. Once that conversation is happening, nodes can say things to each other to organise searches for and downloads of files. We saw forged TCP reset packets that stop some of the nodes from being able to converse with each other in the first place...Link (via Isen)
It isn't just BitTorrent and Gnutella that are affected. Kevin Kanarski has reported that Lotus Notes (a suite of software that many businesses use for email, calendaring and file sharing) is also being interfered with. We haven't tested this ourselves yet, but Kanarski's packet traces look a lot like the ones we've collected with BitTorrent and Gnutella.