I use uTorrent (a p2p prog) and it requires that a port is open for communications. This is really needed.
uTorrent does set it up automatically on the windows firewall but not on other firewalls like my ZA PRO 8... and I don't know how to set it up.
Ideally, i would prefer to open this port only when uTorrent is running.
In your explanations, assumes that the port number is 12345.