Block p2p downloading in my office?

Solution 1:

Both good answers from satanicpuppy and cschreiner. I'll add my $0.02. If the linksys router will accept Tomato firmware (http://www.polarcloud.com/tomato), you can use the Traffic Shaping/QoS options to de-prioritise anything you want. I find the Tomato QoS/Shaper works better that anything else I've tried (DDWrt and pfSense)

I am using Tomato firmware right now in a somewhat similar situation where I have multiple people using one connection, and pay per MB of usage.

My Linksys WRT54GL usually has uptimes of around 60-120 days, and it does work very well.

Solution 2:

I would suggest a two pronged tactic:

1. Set up rules to only allow traffic for specific services of your choosing, such as DNS, web, https, ftp, mail, etc. Trying to block the ports used by P2P apps is a losing battle, as in many cases you can change the port used in the application's preferences or switch to another application.

2. The other thing to do is talk to the boss or person who makes financial decisions (if this isn't you) and make it a policy that this is not allowed and let the employees know that you are logging what is going on, and anyone using P2P will be fired. It isn't worth your time to be fighting a constantly escalating war to find a foolproof way to keep people from using P2P.

I suggest SonicWall firewalls which can do both internal to any rules, and have logging and reporting options. The tomato firmware mentioned earlier may have these capabilities as well—I am not that familiar with it.