SMC anti-spam milter 1.7

SMC non-context E-mail filter - is an software application designed to significantly reduce the amount of SPAM/UCE (junk-mail) you receive. SMC uses a dynamic local and DNS based remote "whitelists" (for known/trusted senders), DNS based "blacklists" (for undesired senders), and an original "autoauthentication" system (for unknown, but legitimate senders).
In additional SMC has a set of useful features which allows to preserve mail recipients from dangerous message attachments, HTML includes. SMC is an Sendmail milter (plugin), which stops the junk-mail without receiving one.
SMC uses 3 original algorithms, one of which is "Check relay by NS" simulates a dynamical whitelist and will always accept the messages from mail systems satisfying to following conditions:
1. Mail domain name (the host part of the senders e-mail address) must have an MX records;
2. Mail domain name and the connection host address must be resolved;
3. Connection host must be listed at the one of nameservers which hold the senders mail domain name.
The second from the developed algorithms is a "check delays" algorithm which is based on statistical check of delivery delays, generated by a [tempfail] return code, that allows to exclude a direct receiving of a mail, which not passed through the standard mail server.
NOTE: Using this feature the delivery of the mail from unknown, but legitimate senders will be delayed for a count of 10-minutes checks, which setted by the "maxcount" configuration parameter.
And the third of original algorithms is "auto-authentication" algorithm: The sender of a "mail contact" (sender-recipient pair) means as authenticated (whitelisted) if the filters statistics module has registered the both of a sended forward (request) and a recieved backward (reply) messages of this contact. The messages from the such authenticated senders will never be delayed by the previous "check delay" algorithm.
Enhancements:
- CLOSE_WAIT problems have been solved (a critical bug).
- There is a critical bugfix to prevent DNS storms.
- All of the resolver functions use the local resolver context.
- Automake and autoconf support have been added.