Ask the head of the IT Department (or whatever they're called - a teacher/professor basically) to help you adjust the settings. Chances are that if you CAN'T chat at the University, then you're not meant to

- If they refuse to help you so you can use IRC, then it's not allowed.
I'm afraid we do not help with evading the policies of a school/college/university or work place, no matter what the circumstances. Also, you'll find that many networks will not allow connections through
open proxies such as HTTP, socks or wingate in order to prevent abuse.
The reason you can chat at home and not at University is most likely due to that firewall, and maybe some sort of filter to block such things as IRC or 'adult entertainment' websites (fear the political correctness!)
Sorry!
Regards,