Routing at our last LAN was performed by pfSense http://www.pfsense.com/ . We utilized QoS, initially setup using the Traffic Shaper wizard. I selected all possible P2P protocols, and allocated them all collectively 1bit/second, or effectively 0 (they don't support zero unfortunately). I also limited our download to 3Mbps (later upped to 5Mbps after I found out we were locked at the port at 10Mbps), and upload to 500Kbps. I also setup the captive portal, and limited each user's bandwidth to 1Mbps down, 100Kbps up. NOTE: servers may require more than 100Kbps up, particularly Valve servers as their VAC requires some transfer bandwidth to verify users. This can be accomplished by adding an additional rule to the Traffic Shaper, placing servers at a different QoS level than most traffic.

The file server at the last LAN was a Dell PowerEdge server, containing 2 2.4GHz Xeon processors with hyperthreading (P4 era), 6GB ECC-RAM, 3 60GB 10k RPM SCSI UW3 HDDs, 3 30GB 10k RPM SCSI UW3 HDDs, gigabit ethernet & 10/100 ethernet. It was running Ubuntu server, with lighttpd being used to share the files. SSH & Samba were used to transfer the files to the server. It also hosted FEAR & BF2 servers, neither of which were utilized during the LAN. It may host the Warsaw server next LAN, as that got a fair amount of use and is incredibly light-weight.

This one is particularly annoying, as the Linux client has a known bug in which it does not support LAN mode http://fpsadmin.com/forum/showthread.php?t=14009 . I have gotten around this issue by null-routing the Activision authentication server, the URL of which escapes me at the moment. If you do this, you can setup the Linux server without worrying about having internet users crash our LAN. CoD4 includes integrated voting, the only changes often requested at LANs are Hardcore mode, which is a simple console edit away.