See also:

• Computers: Internet: E-mail: Spam: Filtering  (68)

• The Antispam Home Page - Instructions to automatically filter your e-mail, defend your site from exploitation by the spammers
• Blocking Mailed Spam - This article discusses several alternatives available to sites that want to block mailed spam.
• Kai's SpamShield - Sendmail add-on that provides rate control and volume limits for Unix-based mail servers. Can stop spam from ISP's own customers, and mail bombers.
• milter.org - A weblog focused on sendmail milter API.
• milter-regex - milter-regex is a sendmail milter plugin that allows to reject or discard mail based on regular expressions matching SMTP envelope parameters and mail headers and body.
• PTSMail Utilities - A commercial email management utility for Unix sendmail servers utilizing the Milter API. Includes anti spam/virus filter, recovery of rejected email, a web/Sendmail Configurator with reporting/analysis capabilities, and keeps copy of all email. Possibility to order free 15-day licence.
• The Spam Series - Email - A series telling everything about the Internet nuisance, spam, from your About.com Guide.
• Using check_* in sendmail 8.8 - sendmail 8.8: using the check_* rules to prohibit unauthorized relaying through your sendmail server and to reject UBE from well known addresses