NAME

Mail::Qmail::Filter::DMARC - verify DMARC policy of mail message

SYNOPSIS

    use Mail::Qmail::Filter;

    Mail::Qmail::Filter->new->add_filters(
        '::DMARC' => {
            skip_if_relayclient => 1,
        },
        '::Queue',
    )->run;

DESCRIPTION

This Mail::Qmail::Filter plugin verifies if the incoming e-mail message conforms to the DMARC policy of its sender domain:

  1. The plugin is skipped if imported with feature :skip_for_relayclient and the message comes from a relay client.

  2. We check if the message contains a valid DKIM signature matching the domain of the From: header field. If this is the case, the e-mail is passed on.

  3. If not, a SPF check is done, and a Received-SPF: header field is added to the message. Then we check if the message is aligned with its sender's DMARC policy. A DMARC-Status: header field is added.

    If the message does not align to the policy, the policy advises to reject such messages and when the plugin is used with the :reject feature or the environment variable DMARC_REJECT is set to a true value, the message will be rejected with 554 Failed DMARC test.

Please note: This only works for valid sender addresses. If the message has no valid RFC5322.From, this filter will not reject the message, because Mail::DMARC does not like invalid sender addresses. If you also happen to not like these, please use Mail::Qmail::Filter::ValidateFrom and/or Mail::Qmail::Filter::ValidateSender before this filter.

OPTIONAL PARAMETERS

dry_run

When set to a true value, the message is only marked, not rejected.

reject_text

Reply text to send to the client when the message is rejected.

Default: Failed DMARC test.

SEE ALSO

"COMMON PARAMETERS FOR ALL FILTERS" in Mail::Qmail::Filter, Mail::Qmail::Filter::ValidateFrom, Mail::Qmail::Filter::ValidateSender

LICENSE AND COPYRIGHT

Copyright 2019 Martin Sluka.

This module is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at:

http://www.perlfoundation.org/artistic_license_2_0

Any use, modification, and distribution of the Standard or Modified Versions is governed by this Artistic License. By using, modifying or distributing the Package, you accept this license. Do not use, modify, or distribute the Package, if you do not accept this license.

If your Modified Version has been derived from a Modified Version made by someone other than you, you are nevertheless required to ensure that your Modified Version complies with the requirements of this license.

This license does not grant you the right to use any trademark, service mark, tradename, or logo of the Copyright Holder.

This license includes the non-exclusive, worldwide, free-of-charge patent license to make, have made, use, offer to sell, sell, import and otherwise transfer the Package with respect to any patent claims licensable by the Copyright Holder that are necessarily infringed by the Package. If you institute patent litigation (including a cross-claim or counterclaim) against any party alleging that the Package constitutes direct or contributory patent infringement, then this Artistic License to you shall terminate on the date that such litigation is filed.

Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.