I've been working way too much lately, but at least I've taken the time to install a new spam filter on my mail server. It was actually only a very small patch to the qmail source that was needed to get it to filter mail through policyd. Policyd is primarily made for Postfix, but seems to work great with qmail too. That puts an end to my own greylisting project, which only greylisted on source-IP/24. The "greysmtpd" app was working as it should but there were too many spammers in the world to make it effective enough.