Torrents can use any port they want, but they are user initiated things, so if you aren't running a bit torrent client you shouldn't need to worry about them. Even if you use a client to download a file, as long as you turn it off after you are done you will not be uploading anything.
Most linux distributions include a firewall which you can turn on and block all incoming connections. However if you initiate a connection (by say, running a bit torrent client) the firewall will allow related connections so that the program you are running will work ask expected.
I hope this addresses your concern, please clarify why you are worried about torrent connections in particular if it does not.