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NAME
The dovecot antispam pugin.
DESCRIPTION
The dovecot antispam plugin watches a defined spam folder (defaults to
"SPAM"). It works together with a spam system that classifies each
message as it is delivered. When the message is classified as spam, it
shall be delivered to the spam folder, otherwise via the regular
filtering file the user may have (maildrop, sieve, ...). Now the user
has everything classified as spam in the special spam folder, everything
else where it should be sorted to.
This is not enough because our spam scanner needs training. We'll
occasionally have false positives and false negatives. Now this is the
point where the dovecot antispam plugin comes into play. Instead of
moving mail into special folders or forwarding them to special mail
addresses for retraining, the plugin offers two actions for the user:
1. moving mail out of the SPAM folder and
2. moving mail into the SPAM folder.
The dovecot plugin watches these actions (and additionally prohibits
APPENDs to the SPAM folder, more for technical reasons than others) and
tells the spam classifier that it made an error and needs to re-classify
the message (as spam/not spam depending on which way it was moved.)
The advantage of this approach is that the mail ends up in the right
target folder directly and needs not be touched twice.
INSTALLATION
First copy the 'defconfig' file to '.config' and edit it as necessary.
You need to have the dovecot headers installed and possibly other things
depending on the backend you choose. Then, assuming you have configured
the INSTALLDIR correctly, simply run 'make install'.
If you do not wish to use the install target, simply copy the plugin
(that is, the file lib90_antispam_plugin.so) to your dovecot imap plugin
directory; by default this is /usr/lib/dovecot/modules/imap/ or any dir
you have configured (look for the mail_plugin_dir configuration
directive.)
Open your dovecot configuration file (usually /etc/dovecot/dovecot.conf)
and add the antispam plugin to the imap protocol section:
protocol imap {
mail_plugins = antispam
# mail_plugin_dir = /usr/lib/dovecot/modules/imap
}
CONFIGURATION
Aside from the build-configuration done in the '.config' file, you have
the following run-time options (shown along with the default):
plugin {
##################
# GENERIC OPTIONS
# mail signature (used with any backend requiring a signature)
antispam_signature = X-DSPAM-Signature
# semicolon-separated list of Trash folders (default unset i.e. none)
# antispam_trash =
# antispam_trash = trash;Trash;Deleted Items
# semicolon-separarted list of spam folders
antispam_spam = SPAM
###########################
# BACKEND SPECIFIC OPTIONS
#
# dspam-exec plugin:
# dspam binary
antispam_dspam_binary = /usr/bin/dspam
# semicolon-separated list of extra arguments to dspam
# (default unset i.e. none)
# antispam_dspam_args =
# antispam_dspam_args = --user;%u # % expansion done by dovecot
# antispam_dspam_args = --mode=teft
}
AUTHORS
Johannes Berg, Frank Cusack, Benedikt Boehm, Andreas Schneider
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