Implement ARC as addon to DMARC
ARC solves some problems of DMARC and should be implemented as well
Oh yes, Plesk definitely needs ARC. Without ARC, e-mail forwarding is rendered useless if any sender (to a forwarded address) has implemented a DMARC policy other than none.
This is not a matter of Plesk admins requiring this feature, this is a must-have if Plesk wants to continue to be used as a mail server. The internet is moving on, all major e-mail providers push the implementation of DMARC and support ARC.
Since we cannot control sender domains we have no option to mitigate this issue on the Plesk side if e-mail forwards are in place.
Please implement this!
This has become an issue for me as well, to the point customers are now looking at alternate solutions.
ARC is already implemented / supported at major mail providers: http://arc-spec.org/?page_id=79 (e.g. Gmail, Office 365) and Mailman.
Postfix compatible implementations exist via (at least) OpenARC (Trusted Domain Project) and Rspamd
Christian Heutger commented
DMARC will fail similar to SPF on forwarding, which is e.g. supported and widely used in Plesk. You implemented SRS to prevent SPF to fail, ARC is the same for DMARC.