Tagboard with domain name block

[MaGiCSuN]

Does anyone know of a script that lets you allow to block certain domain names from a tagboard?

I have a friend that has a spammer on her site but she can't block IP's since he hasn't got a static IP.

I searched and searched through google.com but can't find any script that does this very simple thing though ..

Thanks !

Love,
Mirna