Port 3724 I believe.

For port forwarding, first thing you must do is set up a static ip address: Setting up a Static ip Address

Then choose your router brand & model -> PortForward.com - Free Help Setting up Your Router or Firewall click on the model -> click the skip this add at top right of next page -> choose World of Warcraft from the alphabetical list of purposes for port forwarding.

At university they may well have various ports blocked. Else they have a p2p shaper .. which might apply to games & sharing programs. It can either shape the bandwidth or totally block them. Such shapers can detect the type of protocol that is being used to communicate with other gamers/p2p sharers.

can this be detected by any of the uni admins do you know ?

and @ sleepless

i am fully aware of the addictiveness of wow, but not every body falls prey to this, i played wow while doing my GCSE's and my A Levels and it didnt affect the outcome at all, your quite right that alot of people are as you said but not all of them and to stereo type all people at university in the same way is a poor oversight on your behalf im afraid, i appreciate your concern and taking the time to reply tho

cheers

chris