how to block the peer to peer site

[John]

Hello Team,

We would like to ask how to block peer to peer site (torrent) in ASA firewall.

[joseoroz]

Hello John,

This document has instructions on how to create rules for blocking P2P on the ASA. However those applications normally relay on encrypted mechanisms and port randomizers that make it more difficult to catch users and also have on mind that unfortunately the firewall doesn't inspect encrypted traffic by itself. 

http://www.cisco.com/c/en/us/support/docs/security/asa-5500-x-series-next-generation-firewalls/98684-pixasa-imblock-config.html