Does µTorrent support UPnP (Universal Plug Play)?
Yes. As of 1.5.1 beta build 462, UPnP works on ALL OSes. You can turn it on in Connection. If it works properly, then you should see the port has been mapped in the Logger tab, and green network light once you receive an incoming connection. You can use the port checker in the Speed Guide (Ctrl G) to see if it really is working properly. If it never turns green after running torrents for a while, or says Unable to mape UPnP port, it most likely means that something went wrong, usually a software firewall blocking incoming connections. See this question for more info about the UPnP error. If all else fails, the port may still have to be forwarded manually. See How do I forward ports? for an explanation of what UPnP is for and other info related to forwarding ports.
