• Scored evaluation of RBL/RHSBL results
• Scored evaluation of DNS relationships and correctness of HELO and MAIL FROM arguments (MX, A, subdomains) in respect to Client DNS records (PTR, A, subnets) - weighted by RBL scores. It tries as best as possible to find a DNS wise verified relationship between (Client IP, Hostname) and (HELO or FROM), this travells down to subdomains and subnets
• SPAM Cache for "user@senderdomain.tld-123.123.123.123" hashes (precedence of HAM cache)
• HAM Cache for "senderdomain.tld-123.123.123.123" hashes
• Multirecipient aware
• May be used for "all but some specific user" or "only for specific user" via postfix restriction classes. The same goes for clients.
• Own RBL Lookup routine for very fast and cheap DNS RBL/RHSBL lookups
• Configuration file for own adjustments
• Absolutely no database dependencies. No MySQL either ;-)!
• Fast, optimized perl - designed for large scale environments

Benefits:

• In contrast to postfix' reject_rbl_client, reject_rhsbl_client, reject_unknown_* and reject_non_fqdn_helo, one hit must not mean that the client will be rejected
• Bandwidth savings: You are able to reject based on "weights" before the DATA content will be received
• CPU savings: Postfix and after queue content filter have less to do as they operate on full content; policyd-weight doesn't - as it fires in very early at RCPT TO stage
• Other resource savings: queue resources, disc access resources, quarantine space