spamassassin (1) - Linux Manuals

spamassassin: extensible email filter used to identify spam

Command to display spamassassin manual in Linux: $ man 1 spamassassin

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::AskDNS
    Mail::SpamAssassin::Plugin::AutoLearnThreshold
    Mail::SpamAssassin::Plugin::Bayes
    Mail::SpamAssassin::Plugin::BodyEval
    Mail::SpamAssassin::Plugin::Check
    Mail::SpamAssassin::Plugin::DKIM
    Mail::SpamAssassin::Plugin::DNSEval
    Mail::SpamAssassin::Plugin::FreeMail
    Mail::SpamAssassin::Plugin::HTMLEval
    Mail::SpamAssassin::Plugin::HTTPSMismatch
    Mail::SpamAssassin::Plugin::Hashcash
    Mail::SpamAssassin::Plugin::HeaderEval
    Mail::SpamAssassin::Plugin::ImageInfo
    Mail::SpamAssassin::Plugin::MIMEEval
    Mail::SpamAssassin::Plugin::MIMEHeader
    Mail::SpamAssassin::Plugin::Pyzor
    Mail::SpamAssassin::Plugin::Razor2
    Mail::SpamAssassin::Plugin::RelayEval
    Mail::SpamAssassin::Plugin::ReplaceTags
    Mail::SpamAssassin::Plugin::SPF
    Mail::SpamAssassin::Plugin::SpamCop
    Mail::SpamAssassin::Plugin::URIDNSBL
    Mail::SpamAssassin::Plugin::URIDetail
    Mail::SpamAssassin::Plugin::URIEval
    Mail::SpamAssassin::Plugin::VBounce
    Mail::SpamAssassin::Plugin::WLBLEval
    Mail::SpamAssassin::Plugin::WhiteListSubject

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/3.004000
/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/mail/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/mail/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.