Gateway restriction problems
 

I have a redhat 9 server, it's running as a public server. We got a bit problems with people using p2p, and i need a way to ban them, and the only way i know how ís with iptables, and it was working fine until they started to use static ip-addresses. So what i need is a simple way to either force them to use DHCP or an easy way ban static IPs.
Also if Anyone knows a good way to monitor how much bandwidth the the peer's using.
Your help is appreciated!

ps. sorry, my english is bad
pps. I'm new at linux, so not so many advanced scripts

Do you control the clients the users use? If so, take away root priveleges and set the client to use DHCP. Only root can issue change parameters to ifconfig.

No i have no access to the clients, so what ever there have to be done has to be on the server.