Ubuntu Servers :: How To Block Torrents By Using Squid Or Firewall

I've been all around the net and can't find a "simple" answer how to block our LAN users from downloading torrents. Is it really that difficult?

Here's our setup:

1. The Server's Configs:

2. sudo gedit /etc/squid/squid.conf

3. sudo gedit /etc/rc.local (to start Firewall rules on bootup)

4. Server NOT a DHCP Server

5. No other iptables rules are configured, just the above ones.

Before in a 1 NIC setup, I blocked Workstations MAC addresses in the Router + Squid Proxy Server (Not Transparent), it worked, but some Online Java Apps didn't work and users can't send/receive email so I abandoned the method.

Now, I installed transparent Squid Proxy with 2 NIC cards, it works, but workstations can still download torrents! I know Squid doesn't block ports, right? So the answer must lie in Iptables Firewall? I basically use Squid just to deny access to Facebook, Friendster, or other "unproductive sites".

Quote:

How to block torrent downloading by using a Firewall? Or is there another "simple" way?

I've heard that it's better just to allow regular ports (80, 22, 465, etc...) then block all the rest, this way, you can prevent unnecessary ports.

I'm not an Iptables/Firewall expert so can you pls. explain it a bit more detailed if that's the case.

I'm also aware of just telling our users NOT to download torrents, but I just want to prohibit it entirely.

I know I will be the most "uncool" employee in our office.