chat hijacking / user banning

[twinpawer]

Hi,

We have implemented this chat component for one of our websites and all in all it works great. However, lately some random user started logging in and hijacking the chat, writing obscene words, that the chat is closed permanently, etc. This is scaring away the genuine users, and basically killed most of the traffic.

Given that this is public-accessible, are there any ways one can stop such users from such malicious activities? Is it possible to ban users by IP? However, if the IP changes I guess that still is a problem. Any ideas?

Thanks a lot in advance!