- If you're already familiar with SpamAssassin
- What it is and how it works
- Whitelisting and blacklisting
- Running SpamAssassin from webmail
- Running SpamAssassin from procmail
- Filtering foreign-language mail with SpamAssassin
What it is and how it works
Panix makes SpamAssassin available and supports it for filtering spam as it is delivered to your account.
Rather than using specific addresses, SpamAssassin uses a series of tests to look for "key phrases" and other indicators of spam in an email message. Each of these tests has a point value, and the message gets a score that is the total of the points for all the tests it matches. If the score is above a given threshold, the message is treated as spam. You can adjust the point value for any of the tests, and/or you can change the threshold setting. You can also control what happens to mail that scores in the Spam range: You can trash it without looking at it, put it into a special folder of your own choosing, or put it into your inbox with a special header to distinguish it from the rest of your email.
For full details, please see the SpamAssassin web page at http://spamassassin.apache.org/.
Because SpamAssassin is third-party software, upgrades may result in changes in the point value of any of the rules. (We make occasional local changes, but they are rare.) We advise users to whitelist addresses they wish to protect.
Panix users can enable Spamassassin either from the webmail interface or via procmail. Please do not use both. (Not only does it waste system resources, it complicates the process of determining what might have happened to a given piece of mail.)
Whitelisting and blacklisting
Whitelisting simply means adding a known good address to a list that will either bypass SpamAssassin entirely or will give messages from that address a very low (i.e. large negative number) score. SpamAssassin's built-in whitelisting function is easy to enable from the webmail interface. If you're using procmail to run SpamAssassin (spamc), you have an alternative, described here.
You might think that SpamAssassin would also be good for blacklisting spammers' addresses, but this is not the case. First, spammers tend to use one-time addresses, or forge legitimate addresses. Blacklisting these accomplishes nothing and might cause mail from legitimate senders to be trashed. Also, the file that contains these addresses becomes bloated. Once the file becomes too large (over 1024 non-blank lines), SpamAssassin stops working entirely. Blacklisting is fine for dealing with small numbers of specific known addresses-- former friends whose email is no longer welcome, say.
Other SpamAssassin Resources:
- The SpamAssassin wiki, in which tests and their
default values can be looked up:
Unfortunately, Spamassassin no longer maintains a comprehensive list of all existing tests, due to the frequency with which the tests are updated. The most recent list of tests can be seen at https://spamassassin.apache.org/tests_3_3_x.html. Please be aware that it is missing at least a year of development, that many of the tests listed may have been deprecated, and that some of the wiki links might not work.
- The SpamAssassin manpages:
Mail::SpamAssassin::Conf(3) (user_prefs config)
- The spamassassin.org README file offers additional documentation (some of it relevant and some not).
Last Modified:Friday, 04-Dec-2015 15:01:15 EST
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