Over the last couple of weeks I have been running a live fire exercise for some of my anti weblog spam software. This is a “new and improved” version of my auto banning plugin. This version uses the Movable Type 3.2 junk feature to track the set of addresses to ban. It is configured with a count such that when an address is in the junk list that many times, it gets banned via an .htaccess file.
It took two weeks and 4934 addresses before the spam stream slowed to a trickle. It actually slowed down a couple of days ago, but I had set the junk expiration date low enough that junked objects were getting culled (which also removes those addresses from the ban list). The expire date was 30 days, so apparently even after 30 days of continual “access denied”, the spam bots keep on pounding.
The important result is that I now have a rough bound for the number of addresses required to reduce spam attacks to a tolerable level and it is small enough that maintenance is not a performance bottleneck. Now I just need to package it up so normal mortals can use it.