open source implementation of the Sender ID specification as defined
by the Internet Engineering Task Force's (IETF) MARID Working Group
(Mail Authorization Records in DNS).

sid-milter implements the -core and -protocol specifications.
Additionally, sid-milter implements the "SPF Classic" record protocol
(v=spf1) as defined by the SPF community.

WWW: http://sendmail.net/sid-milter/