SpamAssassin is an open-source mail filter project designed to identify spam. It uses a diverse range of tests and has been shown to be very effective in separating spam from non-spam mail.
Because SpamAssassin integrates multiple techniques and is being continuously updated and extended it has an advantage over other anti-spam systems.
Although SpamAssassin also uses Bayesian statistical techniques to analyse mail, it also tests for many features that are very hard for spam senders to avoid. The spammer's objective is to spread advertising (or some message) as widely as possible, with as little cost to themselves as possible. In order to accomplish this the spammer must employ many methods that are not typical of regularly sent mail. For example, spammers may attempt to obscure the actual message using images or unnecessary HTML markup and SpamAssassin will factor this in when assessing a message.
See the SpamAssassin-tab for information on configuring the SpamAssassin integration.
You can reach this tab from Options | Anti-spam ...
What is SpamAssassin? Read morew ...
What does SpamAssassin test for? AnswerS ...
Most users find that if they receive mail via SMTP and have enabled Greylisting that they get little additional benefit from using SpamAssassin as well. Greylisting also uses fewer machine resources.
We recommend enabling Greylisting prior to SpamAssassin where practical.
SpamAssassin is managed from the Console, at
Options | Anti-Spam...
at the SpamAssassin-tab (see right).
Bayesian Anti-Spam does not also need to be enabled
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Working with SpamAssassin for Win32 with Mailtraq
Download the SpamAssassin files to get started.
Download SpamAssassin for Win32 here or here
These instructions are valid for both 32-bit and 64-bit machines.
If you are a new user all you need do is:
to its own folder (whether unzipping or doing an actual install)
and then enter the full path to spamd as illustrated:
(e.g. "C:\Program Files\SA\spamd.exe" or to
C:\Program Files (x86)\ on 64-bit machines)
into the "Server address or path to spamd.exe" edit box.
Enter the path without " " marks.
Once that is done Mailtraq will automatically
start and manage the spamd.exe process.
And set the configuration as illustrated right.
Shutdown and then restart Mailtraq.
(Note that the dialog box illustrated was updated in build 126.96.36.1994 - see below for previous dialog)
Important update to SpamAssassin for Year 2010+ issue - read more...
Modes of Operation
There are three modes of operation for SpamAssassin.
1. None (disabled)
2. Assisted (Scan all messages ...) - All incoming mail is checked in "Receipt" mode as an additional stage in the SMTP or POP3 sequence
3. Replace (Replace Bayesian ...) - The Bayesian Analyser is disabled and replaced with the SA test which produces a score that is used in exactly the same way that the Bayes score was used.
The reason for 3 is that it allows the existing scoring and training infrastructure (for example, in WebMail) to be re-used. The Bayesian Trainer is also replaced with the "tell" spamd command.
The reason 2 mentions "local recipients" is that in that model outgoing mail (mail for non-local domains) is not checked. This is partly because every time you test a message with SA it self-teaches and you don't want to skew it with mail that is presumed non-spam.
Users who previously installed this download: SpamAssassinForMailtraq.msi
should uninstall that package and follow the instructions above for New Users as the official SpamAssassin download is now compatible with Mailtraq.
Installation instructions Updated 09/03/2008
We suggest you create a User in Mailtraq called spam and provide webmail access to that mailbox, and then configure the Anti-spam as illustrated above. It is then a simple matter for any user with webmail access to the spam mailbox to check for false-positives. You should set the Archive properties of the spam mailbox to delete messages after a period of time.
SpamAssassin can be run in conjunction with Mailtraq's Bayesian analyzer (as illustrated) or can be used to replace Mailtraq's analyzer by selecting the bottom radio-button in the dialog.
You will get the best results if you run SpamAssassin in conjunction (Assisted mode) with Mailtraq's Bayesian analyzer.
Identifying messages excluded by SpamAssassin
SpamAssassin will by default mark messages it detects by changing the Subject line with a prepend of: *****SPAM*****
SpamAssassin: Sender Exceptions - Exempt Local Senders
It is normal to scan all messages for local recipients, however this means there is a short delay as each message is checked as it leaves your local user and is received by Mailtraq.
You can exempt local senders, and local mailing list senders, from this check by adding their local email address in the dialog. You should also enable the White-list and Auto-learn features at the main Anti-spam dialog.
Enter one email address per line, for instance
or use a wildcard entry to apply to all local users:
SMTP Black List settings
If you use Sender Exceptions it is important to follow the guidance here:
Non-local senders before adjusting the default SMTP Black List settings.
Make sure you understand the implications of 'unchecking' - 'Reject non-local senders claiming to be local' if you also Exempt Local Senders from the SpamAssassin check, as it will mean that remote senders who spoof your domain name will not be checked. Follow the advice there on how to allow controlled relaying from legitimate non-local senders without creating a hole in your spam protection by using SMTP-Auth.
1.) The SpamAssassin engine takes several minutes to start after restarting Mailtraq. You may see Mailtraq Event Log entries similar to the following:
[Time] SpamAssassin: "" from (error=Windows socket error: No connection could be made because the target machine actively refused it (10061), on API 'connect')
This simply means that the SA engine was not yet ready to accept connection. No action is required.
2.) SpamAssassin will require at least 1GB of RAM to operate smoothly.
It is possible to tweak how SA works for you - customizing tests, setting trust relations etc.
There is an easy to follow guide to custom configuration included with your SA installation. If you installed SA in the location described above - look in C:\Program Files\SA\doc\Mail_SpamAssassin_Conf.html
Tweaks are applied to the 'cf' files in this location: C:\Program Files\SA\etc\spamassassin
For example - changing the trusted network is applied to 'local.cf' in that folder.
Note that where Mailtraq enters an IP range as 192.168.*.* in SA the same range is entered as 192.168/16
You need to find the "user_prefs" file that is being read by spamd when it is loaded by a service. Unfortunately this varies greatly across different versions of Windows.
In Windows Vista x64, this file is located in
while in Windows 2003 Server x86, this file is located in
C:\Documents and Settings\Default User\.spamassassin\user_prefs.
There is also a discussion of advanced adjustments in the Forum here... that explains how to adjust the spam score when using the MMC version of Mailtraq
It is recommended that you only make one change at a time, and it may be necessary to restart both Mailtraq and the SpamD service, or reboot, to apply the changes.
There is Forum discussion of advanced SpamAssassin configuration here ...
Configuration options prior to 188.8.131.524
Mailtraq supports the latest version of SpamAssassin and now that it is being regularly produced as a Win32 binary there is no longer any need for us to provide our own custom build. You simply install it and tell Mailtraq the path to the spamd.exe file, and it does the rest. The advantage is that administrators can update as often as they wish and have complete control over customization.
Mailtraq News October 2007
Mailtraq introduced support for SpamAssassin for Win32 in 184.108.40.2064