Qmail mail validator https://github.com/mbirth/mail-arc
This is a script meant to be used in qmail before forwarding mail to e.g. Gmail. It will verify incoming mail against SPF, DKIM and more and add the appropriate ARC headers. This makes Gmail (hopefully) accept mails for which there's a DMARC rule with "reject" set.
Usage This filter is meant to be used inline a .qmail file before forwarding. E.g.: mail-arc.py | forward email@example.com To test it, you can throw a mail at it through normal piping: cat mymail.txt | SENDERfirstname.lastname@example.org ./mail-arc.py The output is the mail with additional validation headers.