What are the best ways of stopping flooding/spamming in a forum by people who use alternate accounts?
Are there any ways of banning someone permanently on a forum, other than banning their IP, MAC address, etc...?
I have a problem with flooding/spamming on my forum, and I can't ban this person because his IP keeps changing, and he can change his MAC address within minutes. I don't want to ban an entire domain or ISP, cause it will cause others from accessing the forum.