NAME

Mail::SpamAssassin::Plugin::AuthRes - use Authentication-Results header fields

SYNOPSIS

SpamAssassin configuration:

loadplugin Mail::SpamAssassin::Plugin::AuthRes

authres_trusted_authserv myserv.example.com authres_networks all

DESCRIPTION

This plugin parses Authentication-Results header fields and can supply the results obtained to other plugins, so as to avoid repeating checks that have been performed already.

ADMINISTRATOR SETTINGS

authres_networks internal/trusted/all (default: internal)

Process Authenticated-Results headers set by servers from these networks (refers to SpamAssassin *_networks zones). Any header outside this is completely ignored (affects all module settings).

internal   = internal_networks
trusted    = internal_networks + trusted_networks
all        = all above + all external

Setting "all" is safe only if your MX servers filter properly all incoming A-R headers, and you use authres_trusted_authserv to match your authserv-id. This is suitable for default OpenDKIM for example. These settings might also be required if your filters do not insert A-R header to correct position above the internal Received header (some known offenders: OpenDKIM, OpenDMARC, amavisd-milter).

authres_trusted_authserv authservid1 id2 ... (default: none)

Trusted authentication server IDs (the domain-name-like first word of Authentication-Results field, also known as authserv-id).

Note that if set, ALL A-R headers are ignored unless a match is found.

Use strongly recommended, possibly along with authres_networks all.

authres_ignored_authserv authservid1 id2 ... (default: none)

Ignored authentication server IDs (the domain-name-like first word of Authentication-Results field, also known as authserv-id).

Any A-R header is ignored if match is found.

METADATA

Parsed headers are stored in $pms->{authres_parsed}, as a hash of array of hashes where results are collected by method. For example, the header field:

Authentication-Results: server.example.com;
  spf=pass smtp.mailfrom=bounce.example.org;
  dkim=pass header.i=@example.org;
  dkim=fail header.i=@another.signing.domain.example

Produces the following structure:

$pms->{authres_parsed} = {
  'dkim' => [
    {
      'properties' => {
        'header' => {
          'i' => '@example.org'
        }
      },
      'authserv' => 'server.example.com',
      'result' => 'pass',
      'version' => 1,
      'reason' => ''
    },
    {
      'properties' => {
        'header' => {
          'i' => '@another.signing.domain.example'
        }
      },
      'result' => 'fail',
      'authserv' => 'server.example.com',
      'version' => 1,
      'reason' => ''
    },
  ],
}

Within each array, the order of results is the original, which should be most recent results first.

For checking result of methods, $pms->{authres_result} is available:

$pms->{authres_result} = {
  'dkim' => 'pass',
  'spf' => 'fail',
}

EVAL FUNCTIONS

header RULENAME eval:check_authres_result(method, result)

Can be used to check results.

Reference of valid result methods and values: https://www.iana.org/assignments/email-auth/email-auth.xhtml

Additionally the result value of 'missing' can be used to check if there is no result at all.

ifplugin Mail::SpamAssassin::Plugin::AuthRes
ifplugin !(Mail::SpamAssassin::Plugin::SPF)
  header  SPF_PASS      eval:check_authres_result('spf', 'pass')
  header  SPF_FAIL      eval:check_authres_result('spf', 'fail')
  header  SPF_SOFTFAIL  eval:check_authres_result('spf', 'softfail')
  header  SPF_TEMPFAIL  eval:check_authres_result('spf', 'tempfail')
endif
ifplugin !(Mail::SpamAssassin::Plugin::DKIM)
  header  DKIM_VERIFIED  eval:check_authres_result('dkim', 'pass')
  header  DKIM_INVALID   eval:check_authres_result('dkim', 'fail')
endif
endif