Does anybody know which specific ports kazaa and winmx require open to work properly? We have 3 PCs networked together through a router and accessing the internet through the NTL broadband connection but people seem to pick the exact time that I want to play vietcong online to download stuff from kazaa and winmx which sends my ping through the roof. Ideally what im looking to do is set up some rules on the router to block specific ports to the offending computers while im playing :)

Here's what KaZaA does. It's default setting is port 1214. So, on your router, block based on the IP (or Mac address) of the computer, or computers you are targeting, on port 1214. Done, right?! Not so fast pard'ner.

KaZaA knows to check through from port 1000-4000 in this case. So block those too. Done? Yes, you've slowed it down at this point, quite severely, but only in connection time. If the user sets the time-out a tad higher, or if their machine is particularly quick in connecting, then you're still stuck. This is because...

Next, KaZaA will latch onto port 80. You cannot block port 80 safely. Blocking port 1000-4000 is risky enough, but Port 80 is your internet browsing port. On port 80, KaZaA will then begin to interlace itself with your incoming and outgoing 'surf' traffic. This will cripple your browsing capabilities almost completely. The only way to block this is to establish your network's browsing capabilities to a random port (eg: port 5555) via a proxy server setup. NOW you can fully block port 80 and cripple KaZaA for good. Yet, the configuration to setup the proxy server connection, and conficts in blocking ports, could make this much more complex than it seems.

Simplest Answer: Just tell your employees/roommates to get rid of KaZaA.. much easier !

Scripts can also be built for W2000, etc, which can block the installation of KaZaA, and/or automatically remove existing versions from your network (we're talking about a corporate network here).


Well.. Enjoy blocking your roommates' KaZaA abuse, then play dumb and insist it's the service provider, not the router. It's even more fun to make the blocking disabled for part of the day, so that they continuously get cut-off in the middle of files.

WinMX uses the TCP 6699 and UDP 6257 ports.

For blocking Kazaa would it be better to maybe block the IP or Mac Address of the offending PC ?