Block torrents
http://www.cyberciti.biz/tips/linux-iptables-open-bittorrent-tcp-ports-6881-to-6889.html
http://www.spinics.net/lists/netfilter/msg52436.html
http://www.digitage.co.uk/rope/BlockingBittorrent
http://l7-filter.sourceforge.net/protocols
http://www.dslreports.com/forum/r22229964-Help-blocking-torrents