Clone detection script

[Ed FvC]

Back in the days of IRC, some fancy mIRC scripts were available that would keep track of people currently in a channel and their IP/hostnames. If another user would sign in with the same thing, an alert would pop up.

Is there any way to do something similar, using the Who's Online information? Not a constant monitoring thing, as I'm sure that would rape a server, but just a script one could run from time to time in case one feels suspicious about possible fake users. Perhaps multiple names from the same IP over a 10-15 minute span or something.

We're having a real nasty multiple login/personality problem on my forums and it's a real pain.

Thanks.