Is there a way to detect, in the Exim configuration file, whether a
sender domain has a DMARC record?
As far as Google tells me, the only mention of DMARC in the Exim spec
is the acknowledgement of the OpenDMARC library.
I suppose I should explain the reason, in case there's a better way:
one of my users forwards her email to gmail (which I do via formail in
her .procmailrc). Unfortunately, she gets mail from domains with a
DMARC reject policy - so when I'm forwarding a DKIM-signed message, I
munge it to come from us (using the percent hack, for old times' sake
- yes, the acceptance of incoming percent-hacked addresses for relaying is
tightly tied down:), and strip the signature.
Unfortunately again, one of the domains sometimes sends unsigned
messsages. When they go directly to people, the From: address will
authenticate against SPF, so will still pass; but since they're not
signed, I don't detect and munge them, and of course they don't pass
when relayed from me. I would prefer to avoid munging *all* her
relayed mail, but could cope with munging all mail relayed from a
DMARC protected domain.
--
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.
