A long time ago I setup a bad bot block list for apache, but then gave it up in fear of blocking legitimate requests. I’m now revisiting the concept thanks to my efforts to leverage collaborative software like forums, wikis, and blogs (like this one).

I just found another post about php rbl lookups, which might be a good solution:

http://www.jhurliman.org/index.php/2005/open-proxy-rbl-lookups-in-php/

and here’s the script that orginally got me thinking about this concept:

http://phprbl.init1.nl/

Other links I just found:

http://www.markcarey.com/spamdb/

http://en.wikipedia.org/wiki/Spam_in_blogs

http://en.wikipedia.org/wiki/Internet_bot