Welcome to SpamAssassin! ------------------------ SpamAssassin is a mail filter which attempts to identify spam using text analysis and several internet-based realtime blacklists. Using its rule base, it uses a wide range of heuristic tests on mail headers and body text to identify "spam", also known as unsolicited commercial email. Once identified, the mail can then be optionally tagged as spam for later filtering using the user's own mail user-agent application. In its most recent test, SpamAssassin differentiated between spam and non-spam mail correctly in 99.94% of cases. Since then, it's just been getting better and better! SpamAssassin also includes support for reporting spam messages automatically, and/or manually, to collaborative filtering databases such as Vipul's Razor [1]. [1]: http://razor.sourceforge.net/ The distribution provides "spamassassin", a command line tool to perform filtering, along with "Mail::SpamAssassin", a set of perl modules which implement a Mail::Audit plugin, allowing SpamAssassin to be used in a Mail::Audit filter, spam-protection proxy SMTP or POP/IMAP server, or a variety of different spam-blocking scenarios. In addition, Craig Hughes has contributed "spamd", a daemonized version of SpamAssassin, which runs persistently. Using "spamc", a lightweight C client, this allows an MTA to process large volumes of mail through SpamAssassin without having to fork/exec a perl interpreter for each one. Ian R. Justman has contributed "spamproxy", a spam-filtering SMTP proxy server. This lives in the "spamproxy" directory. SpamAssassin lives at http://spamassassin.org/ or in CPAN, and is distributed under the same license as Perl itself. This module owes a lot of inspiration to Mark Jeftovic's filter.plx, which I used for a long time, and contributed some code to. However, SpamAssassin is a ground-up rewrite with a new, greatly improved ruleset, a different code model and installation system, and hopefully will be easy to adapt for a multitude of applications. [2]: http://AntiSpam.shmOOze.net/filter/ Questions regarding SpamAssassin should be sent to the mailing list: . Installing SpamAssassin ----------------------- The easiest way to do this is using CPAN.pm, like so: perl -MCPAN -e shell o conf prerequisites_policy ask install Mail::SpamAssassin quit On Debian, you can apt-get it from unstable, thanks to Duncan Findlay. Alternatively download the tarfile, zipfile or Red Hat RPM from http://spamassassin.org/ , and install that, like so: [unzip/untar the archive] cd Mail-SpamAssassin-* perl Makefile.PL make make install [as root] Optional Additional Modules --------------------------- In addition, the following modules will be used for some checks, if available. If they are not available, SpamAssassin will still work, just not as effectively -- some of the spam-detection tests will have to be skipped. - Net::DNS (from CPAN) Used to check the RBL, RSS, DUL etc. and perform MX checks. Recommended. perl -MCPAN -e shell o conf prerequisites_policy ask install Net::DNS quit - Razor http://razor.sourceforge.net/ Used to check message signatures against Vipul's Razor collaborative filtering network. Razor is not available from CPAN -- you have to download it from the URL above. Razor has a large number of dependencies on CPAN modules. Feel free to skip installing it, if this makes you nervous; SpamAssassin will still work well without it. - Mail::Audit, Mail::Internet, Net::SMTP (from CPAN) If you want to use SpamAssassin for local delivery to a qmail or MailDir spool, and you do *not* want to use procmail for some reason, you will need to install the Mail::Audit module, and any modules it requires (there's lots of them, unfortunately). This is no longer recommended. If you use procmail, KMail, or you plan to use 'spamd', you will *not* need these. Here's how to install them using CPAN.pm: perl -MCPAN -e shell o conf prerequisites_policy ask install Mail::Audit quit Using SpamAssassin ------------------ Steps to take for every installation: - Install Mail::SpamAssassin on your mail server, as above. - Test it: spamassassin -t < sample-nonspam.txt > nonspam.out spamassassin -t < sample-spam.txt > spam.out Verify (using a text viewer, ie. "less" or "notepad") that nonspam.out has not been tagged as spam, and that spam.out has. The files should contain the full text and headers of the messages, the "spam.out" message should be annotated with "****SPAM****" in the subject line and a report from SpamAssassin, and there should be no errors when you run the commands. Even though sample-nonspam.txt is not spam, nonspam.out will contain a SpamAssassin report anyway. This is a side-effect of the "-t" (test) switch. However, there should be less than 5 hits accumulated; when the "-t" switch is not in use, the report text would not be added. If the commands do not work, DO NOT PROCEED TO THE NEXT STEP, as you will lose mail! If you use Mail::Audit already: - run "perldoc Mail::SpamAssassin" and take a look at the synopsis, it outlines what you need to add to your audit script. - Copy the configuration files (see CUSTOMISING, below) to a known location, so your script can set the appropriate options for the Mail::SpamAssassin constructor to load them. If you use KMail: - http://kmail.kde.org/download.html mentions: The filter setup is the work of five minutes (if that!) if you have a working spamassassin set up. The filter in question is " ." The action is " spamassassin -P" Then, in the advanced options, uncheck the "If this filter matches, stop processing here" box. If you keep this filter at the top, it will analyze any incoming mail, decide whether it's spam or not, and flag it accordingly. [Then add] a second filter behind it, which searches for the added spam-flags and diverts them into a specific spam folder. [...] If you're using procmail: - Make a backup of your .procmailrc (if it exists). cp ~/.procmailrc ~/.procmailrc.bak - add the line from procmailrc.example to ~/.procmailrc, at the top of the file before any existing recipes. That'll process all mail through SA, and refile spam messages to a folder called "caughtspam" in your home directory. - Send yourself a mail message, and ensure it gets to you. If it does not, copy your old backed-up .procmailrc file back into place and ask your sysadmin for help! Here's commands to do that: cp ~/.procmailrc.bak ~/.procmailrc echo "Help!" | mail root If you want to use SpamAssassin site-wide: - take a look at the notes on the website, at http://spamassassin.org/sitewide.html . You may want to use 'spamd' (see below). - another option is Ian R. Justman's "spamproxy", a spam-filtering SMTP proxy server. This lives in the "spamproxy" directory. If you don't use any mail filter just yet, and want to let SpamAssassin handle local mail delivery: - **BEFORE YOU DO THIS** consider using procmail instead (see above), it's recommended for this situation, and less bugs have been reported with it. Notably, use of SpamAssassin with an NFS-mounted mail spool is **NOT SAFE**. Please use procmail! - Make a backup of your .forward (if it exists). cp ~/.forward ~/.forward.bak - Change your ~/.forward file so it reads like this: "| spamassassin || exit 75" - Send yourself a mail message, and ensure it gets to you. If it does not, copy your old backed-up .forward file back into place and ask your sysadmin for help! Here's commands to do that: cp ~/.forward.bak ~/.forward echo "Help!" | mail root - Send yourself sample-spam.txt and make sure it gets tagged: /usr/sbin/sendmail yourusername < sample-spam.txt Other installation notes: - If you get spammed, it is helpful to everyone else if you re-run spamassassin with the "-r" option to report the message in question as "verified spam". This will add it to Vipul's Razor (http://razor.sourceforge.net/), a collaborative spam filtering network, if you've installed the Razor modules. spamassassin -r < spam-message If you use mutt as your mail reader, this macro will bind the X key to report a spam message. macro index X "| spamassassin -r" This is, of course, optional -- but you'll get lots of good-netizen karma. ;) - Quite often, if you've been on the internet for a while, you'll have accumulated a few old email accounts that nowadays get nothing but spam. You can set these up as spam traps using SpamAssassin; see the ''SPAM TRAPPING'' section of the spamassassin manual page for details. If you don't want to go to the bother of setting up a system yourself to do this, feel free to set up a simple alias to forward any mails to -- replace "someaddress" with something to identify you, such as your email addr or website with non-alphanumeric chars replaced by underscores, or similar. This will feed it into my spam-trapping system running on taint.org, where it will be fed into Razor. - The distribution now includes 'spamd', a daemonized version of the perl script, and 'spamc', a low-overhead C client for this, contributed by Craig R. Hughes. This greatly reduces the overhead of checking large volumes of mail with SpamAssassin. Take a look in the 'spamd' directory for more details. - There's also Ian R. Justman's "spamproxy", a spam-filtering SMTP proxy server. This lives in the "spamproxy" directory. - Scores and other user preferences can now be loaded from an SQL database; see the 'sql' subdirectory for more details. - Edward Fang has contributed the 'communigate.sh' script for CommunigatePro (see the 'contrib' directory). Customising ----------- These are the configuration files installed by SpamAssassin. The commands that can be used therein are listed in the POD documentation for the Mail::SpamAssassin::Conf class (see the 'doc' directory). - /usr/share/spamassassin/*.cf: Distributed configuration files, with all defaults. Do not modify these, as they are overwritten when you upgrade. - /etc/mail/spamassassin/*.cf: Site config files, for system admins to create, modify, and add local rules and scores to. Modifications here will be appended to the config loaded from the above directory. - /usr/share/spamassassin/user_prefs.template: Distributed default user preferences. Do not modify this, as it is overwritten when you upgrade. - /etc/mail/user_prefs.template: Default user preferences, for system admins to create, modify, and set defaults for users' preferences files. Takes precedence over the above prefs file, if it exists. Do not put system-wide settings in here; put them in the /etc/mail/spamassassin directory. This file is just a template, which will be copied to a user's home directory for them to change. - $USER_HOME/.spamassassin: User state directory. Used to hold spamassassin state, such as a per-user automatic whitelist, and the user's preferences file. - $USER_HOME/.spamassassin/user_prefs: User preferences file. If it does not exist, one of the default prefs file from above will be copied here for the user to edit later, if they wish. Unless you're using spamd, there is no difference in interpretation between the rules file and the preferences file, so users can add new rules for their own use in the "~/.spamassassin.cf" file, if they like. (spamd disables this for security and increased speed.) Take a look at the "Mail_SpamAssassin_Conf.txt" file in the "doc" directory to see what can be set. Common first-time tweaks include: - required_hits Set this higher to make SpamAssassin less sensitive. - rewrite_subject Turn off Subject-line rewriting with this. - subject_tag When rewrite_subject is on, the subject stamp is *****SPAM*****. This can be used to change it. - ok_locales If you expect to receive mail in non-ISO-8859 character sets (ie. Chinese, Cyrillic, Japanese, Korean, or Thai) then set this. - defang_mime By default, SpamAssassin will 'de-fang' MIME messages, turning them into content-type text/plain. This will turn that behaviour off. Locali[sz]ation --------------- All text displayed to users is taken from the configuration files. This means that you can translate messages, test descriptions, and templates into other languages. If you do so, I would *really* appreciate if you could send a copy back of the updated messages; mail them to . Hopefully if it takes off, I can add them to the distribution as "official" translations and build in support for this. You will, of course, get credited for this work ;) Help With SpamAssassin ---------------------- There's a mailing list for support or discussion of SpamAssassin. It lives at . See http://spamassassin.org/lists.html for the sign-up address and a link to the archive of past messages. Commercial Tests ---------------- There are several tests in the spamassassin configuration file which are turned off by default, namely the mail-abuse.org and bl.spamcop.net tests. The mail-abuse.org tests are RCVD_IN_RBL, RCVD_IN_RSS, and RCVD_IN_DUL; the bl.spamcop.net test is called RCVD_IN_BL_SPAMCOP_NET. These are commercial services, so you need to pay money to use them. Having said that, the bl.spamcop.net service gets my recommendation as the most useful blacklisting DNS service I've found. More information on it can be found at http://spamcop.net/bl.shtml . The mail-abuse.org tests are free for personal use, for now -- so if you're using SpamAssassin as a personal mail filter you may turn them on. More information on the mail-abuse.org services can be found here: http://mail-abuse.org/rbl+/ and http://www.mail-abuse.org/feestructure.html . To turn on the tests, simply assign them a non-zero score, e.g. by adding these lines to your ~/.spamassassin.cf file: score RCVD_IN_RBL 10 score RCVD_IN_RSS 1 score RCVD_IN_DUL 1 score RCVD_IN_BL_SPAMCOP_NET 4 Automatic Whitelist System -------------------------- SpamAssassin includes automatic whitelisting; if a mail sender sends 3 mails which are not matched as spam, their address will be added to an automatic whitelist database. This will mean that further mail from that address will never be tagged as spam, no matter how "spammish" it may appear. For command-line spamassassin users, this happens automatically. 'spamd' needs the '-a' command-line flag to do this. A system-wide auto-whitelist can be used, by setting the auto_whitelist_path and auto_whitelist_file_mode configuration commands appropriately, e.g. auto_whitelist_path /var/spool/spamassassin/auto-whitelist auto_whitelist_file_mode 0777 The spamassassin -W and -R command line flags provide an API to add and remove entries 'manually', if you so desire. They operate based on an input mail message, to allow them to be set up as aliases which users can simply forward their mails to. See the spamassassin manual page for more details. The default address-list implementation, Mail::SpamAssassin::DBBasedAddrList, uses Berkeley DB files to store the addresses. If you are paranoid about concurrency issues, in a high-traffic setup, and/or using NFS, it may be safer to use the directory-based implementation -- Mail::SpamAssassin::DirBasedAddrList -- which uses known-safe UNIX filesystem operations to implement this without the possibility of dangerous race conditions. 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