policyd-weight is a Perl policy daemon for the Postfix MTA (2.1 and later)
intended to eliminate forged envelope senders and HELOs (i.e. in bogus mails).
It allows you to score DNSBLs (RBL/RHSBL), HELO, MAIL FROM and client IP
addresses before any queuing is done. It allows you to REJECT messages which
have a score higher than allowed, providing improved blocking of spam and
virus mails. policyd-weight caches the most frequent client/sender
combinations (SPAM as well as HAM) to reduce the number of DNS queries.