I use the vbstopforumspam modification as it uses a vast database of known spammer ip addys and usernames, a human spammer gets banned and submitted on one forum, his info is automatically blocked on all forums using the mod. I have been using it for a long time now. there are only so many ip addy's a spammer can use. also restricting url's with a limited number of posts helps too.
here is the vbstopforumspam page
https://vborg.vbsupport.ru/showthrea...bstopforumspam