I've got some nasty vandal spamming my wiki using what appear to be random IP addresses that don't seem to be proxies through vanilla ports (tried a couple of simple proxy checker scripts I found, only one out of a dozen or so IPs proxied on port 80 or 8080), so I locked it down and required users to be logged in to edit. This stopped him for awhile, but it looks like he's back now, with a vengeance (http://www.wikidweb.com/wiki/Special:Recentchanges).
His purpose boggles the mind, as it appears to be completely vandalous. He's not even posting urls. However, it's very destructive. Anybody got any ideas? I can only think of two: implement a captcha for every edit or require validated emails for user login. Any other suggestions would be great.
Thanks, Aerik