NAME

spamassassin - extensible email filter used to identify spam

DESCRIPTION

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.

SYNOPSIS

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).

OVERVIEW

    spamassassin              SpamAssassin overview (this section)

CONFIGURATION

    Mail::SpamAssassin::Conf  SpamAssassin configuration files

USAGE

    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

    Mail::SpamAssassin::Plugin::Hashcash
    Mail::SpamAssassin::Plugin::SPF
    Mail::SpamAssassin::Plugin::URIDNSBL

WEB SITES

    SpamAssassin web site:     http://spamassassin.apache.org/
    Wiki-based documentation:  http://wiki.apache.org/spamassassin/

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:

/var/lib/spamassassin/3.002005
/usr/share/spamassassin
/usr/share/spamassassin
/usr/local/share/spamassassin
/usr/share/spamassassin

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

/etc/spamassassin
/usr/etc/mail/spamassassin
/usr/etc/spamassassin
/usr/local/etc/spamassassin
/usr/pkg/etc/spamassassin
/usr/etc/spamassassin
/etc/mail/spamassassin
/etc/spamassassin

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 10_default_prefs.cf before 50_scores.cf and 20_body_tests.cf before 20_head_tests.cf. 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:

/etc/spamassassin
/usr/etc/mail/spamassassin
/usr/share/spamassassin
/etc/spamassassin
/etc/mail/spamassassin
/usr/local/share/spamassassin
/usr/share/spamassassin

TAGGING

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).

INSTALLATION

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

    Mail::SpamAssassin
	Spam detector and markup engine

    Mail::SpamAssassin::ArchiveIterator
	find and process messages one at a time

    Mail::SpamAssassin::AutoWhitelist
	auto-whitelist handler for SpamAssassin

    Mail::SpamAssassin::Bayes
	determine spammishness using a Bayesian classifier

    Mail::SpamAssassin::BayesStore
	Bayesian Storage Module

    Mail::SpamAssassin::BayesStore::SQL
	SQL Bayesian Storage Module Implementation

    Mail::SpamAssassin::Conf::LDAP
	load SpamAssassin scores from LDAP database

    Mail::SpamAssassin::Conf::Parser
	parse SpamAssassin configuration

    Mail::SpamAssassin::Conf::SQL
	load SpamAssassin scores from SQL database

    Mail::SpamAssassin::Message
	decode, render, and hold an RFC-2822 message

    Mail::SpamAssassin::Message::Metadata
	extract metadata from a message

    Mail::SpamAssassin::Message::Node
	decode, render, and make available MIME message parts

    Mail::SpamAssassin::PerMsgLearner
	per-message status (spam or not-spam)

    Mail::SpamAssassin::PerMsgStatus
	per-message status (spam or not-spam)

    Mail::SpamAssassin::PersistentAddrList
	persistent address list base class

    Mail::SpamAssassin::Plugin
	SpamAssassin plugin base class

    Mail::SpamAssassin::Plugin::Hashcash
	perform hashcash verification tests

    Mail::SpamAssassin::Plugin::RelayCountry
	add message metadata indicating the country code of each relay

    Mail::SpamAssassin::Plugin::SPF
	perform SPF verification tests

    Mail::SpamAssassin::Plugin::URIDNSBL
	look up URLs against DNS blocklists

    Mail::SpamAssassin::SQLBasedAddrList
	SpamAssassin SQL Based Auto Whitelist

BUGS

See <http://issues.apache.org/SpamAssassin/>

AUTHORS

The SpamAssassin(tm) Project <http://spamassassin.apache.org/>

COPYRIGHT

SpamAssassin is distributed under the Apache License, Version 2.0, as described in the file LICENSE included with the distribution.