A quick and dirty way to block torrents from being downloaded on your network is to create a LAN firewall rule in PfSense. Click
Firewall -> Rules -> LAN
Ensure that the rule is higher up on the list than the rule with description “Default allow LAN to any rule”. Simply fill out fields in the rule creation according to the screenshot below:
Please note that this is not a foolproof method of blocking torrents. This method simply takes into account the fact that most BitTorrent clients run on higher port numbers, and these ports are of course blocked.