afew

amavisd-milter

amavisd-new

High-performance interface between the MTA and content checkers.

bmf

A fast and small Bayesian spam filter

bogofilter

Bayesian spam filter designed with fast algorithms, and tuned for speed.

courier-pythonfilter

couriersrs

SRS (Sender Rewriting Scheme) wrapper for the courier MTA.

dcc

Distributed Checksum Clearinghouse

dkimproxy

An SMTP proxy that signs and/or verifies emails using the Mail::DKIM module

dkimpy-milter

dovecot-antispam

A dovecot antispam plugin supporting multiple backends

dovecot-antispam-sieve

exim-geoip

exim-p0f

gld

A standalone anti-spam greylisting algorithm on top of Postfix

hashcash-milter

imapfilter

An IMAP mail filtering utility

libmilter

The Sendmail Filter API (Milter)

libopensmtpd

libsieve

A library for parsing, sorting and filtering your mail.

libspf2

libspf2 implements the Sender Policy Framework, a part of the SPF/SRS protocol pair.

libsrs2

libsrs2 is the next generation Sender Rewriting Scheme library

maildrop

Mail delivery agent/filter

mailfilter

Mailfilter is a utility to get rid of unwanted spam mails

mailmasquerade

MailScanner

Free Anti-Virus and Anti-Spam Filter

mapson

A challenge/response-based white-list spam filter

milter-regex

A milter-based regular expression filter

mimedefang

normalizemime

Helper program to normalize MIME encoded messages

openarc

opendkim

A milter-based application to provide DKIM signing and verification

opendmarc

opensmtpd-filter-dkimsign

opensmtpd-filter-rspamd

policyd

Policy daemon for postfix and other MTAs

policyd-weight

Weighted Policy daemon for Postfix

popfile

Anti-spam bayesian filter

postfix-mta-sts-resolver

postforward

postfwd

postgrey

Postgrey is a Postfix policy server implementing greylisting

postsrsd

procmail

Mail delivery agent/filter

pypolicyd-spf

Python based policy daemon for Postfix SPF checking

pyzor

razor

Vipul's Razor is a distributed, collaborative spam detection and filtering network

rblcheck

Perform lookups in RBL-styles services.

rspamd

scmail

a mail filter written in Scheme

sieve-connect

Sieve Command Line Interface

smf-clamd

smf-common

smf-grey

smf-grey++

smf-grey+tym

smf-sav

smf-spamd

smf-spf

smf-zombie

spamass-milter

spamassassin

SpamAssassin is an extensible email filter which is used to identify spam.

spamassassin-botnet

SpamAssassin plugin that attempts to detect messages sent by a botnet

spampd

spampd is a program used within an e-mail delivery system to scan messages for possible Unsolicited Commercial E-mail content.

spamprobe

Fast, intelligent, automatic spam detector using Bayesian analysis.

spf-engine

sqlgrey

SQLgrey is a postfix policy service implementing a grey-listing policy

zdkimfilter

afew

mailfilter

razor

amavisd-milter

mailmasquerade

rblcheck

amavisd-new

MailScanner

rspamd

bmf

mapson

scmail

bogofilter

milter-regex

sieve-connect

courier-pythonfilter

mimedefang

smf-clamd

couriersrs

normalizemime

smf-common

dcc

openarc

smf-grey

dkimproxy

opendkim

smf-grey++

dkimpy-milter

opendmarc

smf-grey+tym

dovecot-antispam

opensmtpd-filter-dkimsign

smf-sav

dovecot-antispam-sieve

opensmtpd-filter-rspamd

smf-spamd

exim-geoip

policyd

smf-spf

exim-p0f

policyd-weight

smf-zombie

gld

popfile

spamass-milter

hashcash-milter

postfix-mta-sts-resolver

spamassassin

imapfilter

postforward

spamassassin-botnet

libmilter

postfwd

spampd

libopensmtpd

postgrey

spamprobe

libsieve

postsrsd

spf-engine

libspf2

procmail

sqlgrey

libsrs2

pypolicyd-spf

zdkimfilter

maildrop

pyzor