zhelev81 wrote:I was reading something like cookie ban or something ,is that one not working anymore ?
The problem with cookies is that they're so easy to clear (unless, maybe, they're "Flash cookies"). Unfortunately, that may be as good as you can do with something like phpBB.
On a client/server chat system that I used to work on, they used a ban system that would mark certain files on the user's PC with a special pattern to ban them. Obviously you don't want Web apps having that kind of control of a user's PC, so that wouldn't work. Also, even that system didn't work perfectly -- fools who were banned would actually reimage their PC to get unbanned.