The functions are:
- Comment Throttling - Exponential back-off to prevent a user on a given IP (or using the same url) from posting too frequently in succession.
- Link checking - Checks for links in the body of the comment and if more than a set number is exceeded, the comment is rejected.
- Black List - Basically MT-Blacklist for Greymatter. It uses the regexp's listed in the file gm-blacklist.cgi to detect suspect content. I currently use the MT-Blacklist list: http://www.jayallen.org/comment_spam/blacklist.txt by just copying that file to gm-blacklist.cgi
All these hacks currently use hard-coded parameters, embedded in the perl source. If you want to change the throttling timers, the maximum number of links allowed, or enable/disable any of these specific checks, you'll have to modify the perl source. They really should use their own parameters in the gm-config.cgi settings but I didn't feel comfortable messing with the gm.cgi script to accomplish this.
For the throttling, you'll need to create a gm-throttle.cgi file and CHMOD it to 666 in your GM CGI directory.
Download here: gm1.3-antispam.zip