Jay Allen has written a very nice document on how to fight comment spam
Jay Allen should know a thing or two about comment spam. Before joing Six Apart he wrote the now famous MT-Blacklist plugin for Movable Type. If you are one of many thats experiencing problems with comment spam, then there really are three things you should take care of to get rid of the problem:
- Upgrade to MovableType 3.x. The new version is better suited to combat comment spam, with features such as comment moderation built in, authentication via Typekey etc.
- Install MT-Blacklist, this plug-in adds features such as url and keyword banning, auto-updates from a spamblock repository etc.
- Last, but not at all least – install the MT-DBSL plug-in. It blocks all the open proxies used by today’s comment spammers. (so they can avoid getting caught by their real ip-address, not to mentioned ip-banned). This plug-in effectively stops over 90% of all the comment spammers on my site right now. Its super easy to install (provided you have the right perl modules already in place) and works like a charm. No switches and no magic involved at all.
That’s a few quick suggestions on how to get rid of comment spam from me, for more in-depth analysis of the comment spam problem, I refer you to the excellent article that Jay has written about the subject: Six Apart Guide to Combating Comment Spam