Bittorrent is a P2P software based on P2P technology. BT downloads files quickly.
Now, BT is very popular and has large numbers of users.
Communication
BT supports TCP and HTTP protocols. BT use TCP port from 6881 to 6889 to login, search and download files.
If the TCP ports from 6881 to 6889 are all blocked, then BT will use HTTP port 80 to download files.
How to block BT?
Because BT can communicate via HTTP and can switch port automatically, so you can not block them only by
disable the ports in the firewall. And BT has no central server, also can not block it by blocking server ip address.
So the only way is using professional tools to block Bitorrent.