Okay, I have yet to find a solution to this problem, but I hope one of you will kindly help me out

I have a shared ADSL connection at home, and my brother, being himself, spends the whole time downloading huge files via P2P and other methods, but P2P is the bigger one. Because of all these massive downloads, he is hogging all the bandwidth, and so browsing the internet is incredibly slow.

Here is my problem: he uses, for example, LimeWire and BitTornado (BitTorrent client). Now, I know for a fact that LimeWire runs on port 6346 as default, and so I can just block outgoing and incoming connections on this port with my firewall, right? This is where the problem arises...With LimeWire, you can just change the listening port to whatever you want, and so there is no way for me to stop my brother constantly changing the port in time for me to block it.

My question is: Is there any way to block the actual kind of traffic, not just the port?

Thanks in advance,

J_K9

*BTW, I use a Linksys WAG54G Router/Modem/Firewall to share my ADSL line.*