NAME

PublicInbox::SaPlugin::ListMirror - SpamAssassin plugin for mailing list mirrors

SYNOPSIS

  loadplugin PublicInbox::SaPlugin::ListMirror

Declare some mailing lists based on the expected List-Id value, expected servers, and mailing list address:

  list_mirror List-Id <foo.example.com> *.example.com foo@example.com
  list_mirror List-Id <bar.example.com> *.example.com bar@example.com

Bump the score for messages which come from unexpected servers:

  header LIST_MIRROR_RECEIVED eval:check_list_mirror_received()
  describe LIST_MIRROR_RECEIVED Received does not match expected
  score LIST_MIRROR_RECEIVED 10

Bump the score for messages which Bcc the list:

  header LIST_MIRROR_BCC eval:check_list_mirror_bcc()
  describe LIST_MIRROR_BCC Mailing list was Bcc-ed
  score LIST_MIRROR_BCC 5

DESCRIPTION

This plugin contains common functions to provide accurate, ongoing mirrors of existing mailing lists. It may be used independently of the rest of public-inbox, it does not depend on any public-inbox code, only SpamAssassin.

ADMINISTRATOR SETTINGS

This plugin has no administrator settings, aside from the need to load it via "loadplugin" and enabling user rules "allow_user_rules 1"

USER SETTINGS

list_mirror HEADER HEADER_VALUE HOSTNAME_GLOB [LIST_ADDRESS]

Declare a list based on an expected "HEADER" matching "HEADER_NAME" exactly coming from "HOSTNAME_GLOB". "LIST_ADDRESS" is optional, but may specify the address of the mailing list being mirrored.

"List-Id" or "X-Mailing-List" are common values of "HEADER"

An example of "HEADER_VALUE" is "<foo.example.org>" if "HEADER" is "List-Id".

"HOSTNAME_GLOB" may be a wildcard match for machines where mail can come from or an exact match.

"LIST_ADDRESS" is only required if using the "check_list_mirror_bcc" eval rule

"list_mirror" may be specified multiple times.

EVAL FUNCTIONS

header LIST_MIRROR_RECEIVED eval:check_list_mirror_received()

The "check_list_mirror_received" function implements "Received:" header checking based on "list_mirror" configuration values.

This rule can be used to score and prevent messages from being injected directly into your mirror without going through the expected mailing list servers:

  ifplugin PublicInbox::SaPlugin::ListMirror
    header LIST_MIRROR_RECEIVED eval:check_list_mirror_received()
    describe LIST_MIRROR_RECEIVED Received does not match expected
  endif

header LIST_MIRROR_BCC eval:check_list_mirror_bcc()

The "check_list_mirror_bcc" function checks for Bcc to mailing lists declared with a "LIST_ADDRESS" via "list_mirror"

Spammers will often Bcc mailing lists; while it's uncommon and strange for valid messages to be Bcc-ed to any public mailing list. This rule allows users to assign a score to Bcc-ed messages

  ifplugin PublicInbox::SaPlugin::ListMirror
    header LIST_MIRROR_BCC eval:check_list_mirror_bcc()
    describe LIST_MIRROR_BCC Mailing list was Bcc-ed
  endif

CONTACT

Feedback welcome via plain-text mail to <mailto:meta@public-inbox.org>

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COPYRIGHT

License: AGPL-3.0+ <http://www.gnu.org/licenses/agpl-3.0.txt>