I found this again a couple days ago: http://marc.info/?l=djbdns&m=99055803519517&w=2

siqpolicyd just had its first “release”. I originally wrote it for myself (and ran it on NSE’s mail server) but since people started asking about it, I thought I’d make a (minimal) page and a tarball release. Grab it, play with it, break it, let me know :)