spamassassin man page

spamassassin — extensible email filter used to identify spam


SpamAssassin is an intelligent email filter which uses a diverse range of tests to identify unsolicited bulk email, more commonly known as "spam". These tests are applied to email headers and content to classify email using advanced statistical methods.  In addition, SpamAssassin has a modular architecture that allows other technologies to be quickly wielded against spam and is designed for easy integration into virtually any email system.


For ease of access, the SpamAssassin manual has been split up into several sections.  If you're intending to read these straight through for the first time, the suggested order will tend to reduce the number of forward references.

Extensive additional documentation for SpamAssassin is available, primarily on the SpamAssassin web site and wiki.

You should be able to view SpamAssassin's documentation with your man(1) program or perldoc(1).


    spamassassin              SpamAssassin overview (this section)


    Mail::SpamAssassin::Conf  SpamAssassin configuration files


    spamassassin-run          "spamassassin" front-end filtering script
    sa-learn                  train SpamAssassin's Bayesian classifier
    spamc                     client for spamd (faster than spamassassin)
    spamd                     spamassassin server (needed by spamc)

Default Plugins


Web Sites

    SpamAssassin web site:
    Wiki-based documentation:

User Mailing List

A users mailing list exists where other experienced users are often able to help and provide tips and advice.  Subscription instructions are located on the SpamAssassin web site.

Configuration Files

The SpamAssassin rule base, text templates, and rule description text are loaded from configuration files.

Default configuration data is loaded from the first existing directory in:






Site-specific configuration data is used to override any values which had already been set.  This is loaded from the first existing directory in:









From those three directories, SpamAssassin will first read files ending in ".pre" in lexical order and then it will read files ending in ".cf" in lexical order (most files begin with two numbers to make the sorting order obvious).

In other words, it will read init.pre first, then before and before Options in later files will override earlier files.

Individual user preferences are loaded from the location specified on the "spamassassin", "sa-learn", or "spamd" command line (see respective manual page for details).  If the location is not specified, ~/.spamassassin/user_prefs is used if it exists.  SpamAssassin will create that file if it does not already exist, using user_prefs.template as a template.  That file will be looked for in:









The following two sections detail the default tagging and markup that takes place for messages when running "spamassassin" or "spamc" with "spamd" in the default configuration.

Note: before header modification and addition, all headers beginning with "X-Spam-" are removed to prevent spammer mischief and also to avoid potential problems caused by prior invocations of SpamAssassin.

Tagging for Spam Mails

By default, all messages with a calculated score of 5.0 or higher are tagged as spam.

If an incoming message is tagged as spam, instead of modifying the original message, SpamAssassin will create a new report message and attach the original message as a message/rfc822 MIME part (ensuring the original message is completely preserved and easier to recover).

The new report message inherits the following headers (if they are present) from the original spam message:

From: header

To: header

Cc: header

Subject: header

Date: header

Message-ID: header

The above headers can be modified if the relevant "rewrite_header" option is given (see "Mail::SpamAssassin::Conf" for more information).

By default these message headers are added to spam:

X-Spam-Flag: header

Set to "YES".

The headers that added are fully configurable via the "add_header" option (see "Mail::SpamAssassin::Conf" for more information).

spam mail body text

The SpamAssassin report is added to top of the mail message body, if the message is marked as spam.

Default Tagging for All Mails

These headers are added to all messages, both spam and ham (non-spam).

X-Spam-Checker-Version: header

The version and subversion of SpamAssassin and the host where SpamAssassin was run.

X-Spam-Level: header

A series of "*" charactes where each one represents a full score point.

X-Spam-Status: header

A string, "(Yes|No), score=nn required=nn tests=xxx,xxx autolearn=(ham|spam|no|unavailable|failed)" is set in this header to reflect the filter status.  For the first word, "Yes" means spam and "No" means ham (non-spam).

The headers that added are fully configurable via the "add_header" option (see "Mail::SpamAssassin::Conf" for more information).


The spamassassin command is part of the Mail::SpamAssassin Perl module. Install this as a normal Perl module, using "perl -MCPAN -e shell", or by hand.

Note that it is not possible to use the "PERL5LIB" environment variable to affect where SpamAssassin finds its perl modules, due to limitations imposed by perl's "taint" security checks.

For further details on how to install, please read the "INSTALL" file from the SpamAssassin distribution.

Developer Documentation

        Spam detector and markup engine

        find and process messages one at a time

        auto-whitelist handler for SpamAssassin

        determine spammishness using a Bayesian classifier

        Bayesian Storage Module

        SQL Bayesian Storage Module Implementation

        load SpamAssassin scores from LDAP database

        parse SpamAssassin configuration

        load SpamAssassin scores from SQL database

        decode, render, and hold an RFC-2822 message

        extract metadata from a message

        decode, render, and make available MIME message parts

        per-message status (spam or not-spam)

        per-message status (spam or not-spam)

        persistent address list base class

        SpamAssassin plugin base class

        perform hashcash verification tests

        add message metadata indicating the country code of each relay

        perform SPF verification tests

        look up URLs against DNS blocklists

        SpamAssassin SQL Based Auto Whitelist


See <>


The SpamAssassin(tm) Project <>

Referenced By

mpop(1), sa-compile(1), sa-learn(1), sa-update(1), spamass-milter(1), spamc(1), spamd(1).

2017-06-06 perl v5.26.0 User Contributed Perl Documentation