66 Configuring and Maintaining Your Server
Setting Up SpamAssassin Spam Filter
To switch on SpamAssassin spam filter:
1 Click the Server shortcut in the navigation pane.
2 Click the Spam Filter icon in the Services group.
3 To let your users set their own spam filtering preferences on a per-
mailbox basis, select the Apply individual settings to spam filtering check
box.
4 If you wish to adjust the amount of system resources the spam filter
should use, type the desired value from 1 to 5 into the Maximum number
of worker spamd processes to run (1-5) box (1 is the lowest load, and 5 is the
highest). We recommend that you use the default value.
5 If you wish to adjust the spam filter's sensitivity, type the desired
value in the The score that a message must receive to qualify as spam box.
SpamAssassin performs a number of different tests on contents and subject line of
each message. As a result, each message scores a number of points. The higher
the number, the more likely a message is spam. For example, a message
containing the text string ―BUY VIAGRA AT LOW PRICE!!!‖ in Subject line and
message body scores 8.3 points. By default, the filter sensitivity is set so that all
messages that score 7 or more points are classified as spam.
When your users receive lots of spam messages with the current setting, to
make filter more sensitive, try setting a lesser value in the The score that a
message must receive to qualify as spam box; for example, 6.
When your users are missing e-mails because your spam filter thinks they are
junk, try reducing filter sensitivity by setting a higher value in the The score that a
message must receive to qualify as spam box.
6 Specify how to mark messages recognized as spam.
At the server level, you cannot set the server-wide spam filter to automatically
delete spam: you can do it only on a per-mailbox basis. So, for the server-wide
policy, you can choose only marking messages as spam: ―X-Spam-Flag: YES‖ and
―X-Spam-Status: Yes‖ headers are added to the message source by default, and if
you want, the spam filter will additionally include a specific text string to the
beginning of Subject line. To include a desired combination of symbols or words to
the message subject, type it into the Add the following text to the beginning of subject of
each message recognized as spam box. If you do not want the spam filter to modify
message subject, leave this box blank. If you want to include into the subject line
the number of points that messages score, type _SCORE_ in this box.
7 If you do not want your users to receive e-mail from specific domains
or individual senders, click the Black List tab, and then add the
respective entries to the spam filter‘s black list:
