How do you block IP?

I'm hosting a chatroom in WinMX and some person on 128K ISDN with IP address 130.203.165.237 entered the room and caused trouble, I blocked that IP address in Sygate Firewall but he's still in the room. Do I have to block IP range? And how do I do that? I used http://visualroute.visualware.com which traced it to Pennsylvania State University...

How can I stop traffic from his computer getting through to the chatroom? Thanks

I think in WinMX, the chatroom is based on the WinMX servers, not yours... thus your firewall won't block his traffic

I have never used Winmx chat so You maybe able to kick the person out of the room and possibly ban them If there is someone with a @ beside their name Like @DeadAddict that means I am the channel operator and I have the power to ban and kick users. I have only been on Irc servers Like Dalnet Etc