Open source DKIM library, MTA filter implementation and associated tools.
A milter program for domain authentication technologies.
Open source DMARC implementation
This is an open source implementation of the draft DMARC specification.
Fork of the OpenBSD spamd for the FreeBSD operating system. See http://www.openbsd.org/spamd/ for the original spamd documentation.
junkfilter is a spam filtering program built on top of the procmail email delivery system. the goal is to create filter sets that will block as much junk email as possible while blocking the fewest legitimate messages.
Keychain Framework is an Objective C Foundation-based framework for accessing Keychain and Security services under MacOS X. It provides convenience wrappers around the CDSA library included with MacOS X, facilities for manipulating keychains, and more.
Heirloom mailx (formerly known as "nail") is intended provide the functionality of the POSIX mailx command with additional support for MIME messages, IMAP (including caching), POP3, SMTP, S/MIME, message threading/sorting, scoring, and filtering.
Camram is a hybrid antispam system combining multiple techniques improving the users e-mail experience.
Active Spam Killer for Windows (AfW) is a challenge/response spam filtering system for the Windows platform. Based on ASK for Linux by Marco Paganini, this project adds a POP3 client/server wrapper and web administration, as well as Windows compatibility
Amber - a "grey list" for Qmail. Amber sits in the tcpserver chain, not accepting or rejecting mail but deferring connections from new IP addresses for some time (default five minutes) before it starts accepting mail from them.
Sendmail Milter written in C to filter out spam.
Archer-Milter , A Sendmail spam filtering solution for system administrators.
A state of the art SMTP relay appliance that kill spam and virus in email
ClamSMTP is an SMTP filter that allows you to check for viruses using the ClamAV anti-virus software. It accepts SMTP connections and forwards the SMTP commands and responses to another SMTP server. Works well with Postfix.
ddnsbl - dynamic dns blacklist maker from sendmail and spamassassin logs.
Evochallenge is a simple Perl based challenge/response mail filter for Evolution on Linux. If you run Evolution, and get buried in spam, Evochallenge can help.
JFetch is an application to download your email through protocols like POP3 and IMAP. The decision of whether to download a mail or not is made through a sequence of filters. The user can easily add customized filters to this sequence.
Fast Greylist daemon as a Postfix Access Policy Delegation Service with a variable extendable rule set. The rules are used for whitelisting, blacklisting and greylisting based on information from the SMTP dialog on a "per delivery attempt" basis.
Magic Spell, a mail client with POP and IMAP support and multiple interfaces.
Mailcash if a plugin for Apple's Mail program that provides hashcash support - that is, verification and generation of hashcash stamps. Refer to <http://www.hashcash.org/> for more information about Hashcash.
Mozilla Thunderbird Barracuda Extension Barracuda Networks SPAM Filter (SpamAssassin) Extension.
Web form that converts pasted rule set from thunderbird/seamonkey msgFilterRules.dat filter file into sieve rules suitable for uploading to an imap mail server and compatible with the sieve rule editor plugin for roundcube 'sieverules' (http://www.roundcubeforum.net/7-third-party-contributions/46-api-based-plugins/4878-sieverules-plugin.html)
libmilter/MySQL based mail filter for sendmail
Postfix Log Parser in Python is a log analysis tool written in python language to get statistic reports and detect anomalous behaviours on a mail server based on Postfix and Cyrus
Pure Perl implementation of the Milter protocol used by Sendmail, including drop-in replacement for the Sendmail::Milter interface.