Here's the official word from the school about this:
"Question:
Why Don't file sharing softwares such as irc, kazaa and gnutella work on the kent servers anymore? Why is other file sharing so slow?
Answer:
When we had problem with network speed a while back, Network Services found it is due to the fact that filesharing software are taking up most of the bandwidth to cause the entire campus network slow down (sometimes ONE user can use MORE THAN 50% of the total bandidth). So, Network Services has implemented a software to limit file sharing priority. IRC has been completely blocked due to the security risks. "