BitTorrent brings the network down

[guest]

I'm using Gentoo on a server that acts as a router. It has two interface cards: one connects to the internal network and the second connects to the internet.

I'm using masquerading with iptables to NAT from the internal network to the internet. It works fine, but I'm experiencing a problem where if someone on the internal network uses BitTorrent for prolonged periods of time, no new connections can be made from the internal network to the internet (the network entirely goes down.) I can always resolve this by replugging the interface card that connects to the internet (uses ifplugd), but this is annoying and not very useful. Is there any way to fix this?

And while we're on the subject, is there a way to throttle P2P related bandwidth to machines on the internal network? It often gets sucked up pretty fast because of things like this.

[sdtester]

I have a similar problem with BitTorrent clogging up the plumbing. I am checking out ipp2p (A module for iptables that identifies p2p packets, like BitTorrent.) There is an emerge for it. I'll let you know what I find.