What are the TCP/UDP torrent ports used by torrent applications?
I am trying to block torrent traffic on my network because it is utilizing too much bandwidth and disrupting my network traffic. What range of torrent ports should I use and what protocol TCP or UDP?
I agree blocking BitTorrent is challenging, and can't really be done effectively with port blocks. The standard torrent ports are 6881-6889 TCP, but the protocol can be run on any port, and the peer-to-peer nature of the protocol means that discovering peers that use unblocked ports is simple.
Blocking BitTorrent traffic could be done with a deep-packet inspection or application firewall, but many BitTorrent clients support encryption that makes DPI less effective. If you own the network and bandwidth is your big issue, then you would be best served by a bandwidth monitoring solution. Quality-of-service (QOS) control and bandwidth caps for endpoints could limit the impact the BitTorrent users are having on your overall bandwidth, without the cat-and-mouse game of trying to block a particular protocol.
Another approach to block BitTorrent would be to block the types of connections that Bittorrent requires. As a peer-to-peer protocol, peers outside your network need to connect. A firewall could prohibit incoming connections to your user subnet while permitting them to your intended outward-facing services. An IPS could put a threshold on the number of incoming and outgoing connections since BitTorrent clients need to connect to multiple peers (and have multiple peers connect to them) in order to function.
If your concern is the legality of the shared content (or if you plan on taking any action against your users), then your best defense is a well-written acceptable-use policy outlining the users' responsibility for their actions and forbidding the use of file-sharing software.
Here is a list of torrents ports that are used:
- TCP/UDP 6881 client connection port
- RCP/UDP 58261
- TCP/UDP 6881 - 6999 Data transfer ports
Although I understand that the user can manually change the port that is being used, but by blocking these torrent ports you might at least cut down the traffic on bit torrent of those that don't know how to get around it.