[talk] dealing with DMARC emails

George Rosamond george at ceetonetechnology.com
Thu Nov 9 10:12:53 EST 2023

In this current era of the email cabal (goog,microsoft,etc), how are
email admins dealing with DMARC emails.

We host our own mail, but the question applies to everyone getting DMARC
emails even if you're stuck in the email cabal mud.

For $job, I usually just use Python dmarcreporting
(https://pypi.org/project/DMARCReporting/) and deal from there, since
it's a shell-based tool and I don't get XML-inspired headaches. But
things have gotten a bit messy with more noisy outgoing sales emails,
and I need to move beyond the manual.

And please recognize that there are more broken/misconfigured SPF and
DMARC records out there than anyone can imagine. I wish I could post a
DMARC email from this AM with emails sourced from a very well-known
tech-heavy company...

The proliferation of 3rd parties, people relying or ignoring
mass-mailing application instructions and the basic reliance on the
email cabal for email hosting are the likely roots of the problem.

At $job we collect and parse out SPF and DMARC (when default) on a huge
number of domains, and it's remarkable how RFC-ignorant the world is.
Hard to believe that this internet thing works at all.

I keep thinking of building something that does the following:

* dealing with automatically grabbing the gzip/zip'd XML attachment,
distinguishing between the 'rua' (aggregate) and 'ruf' (failure) DMARC
emails as they arrive.

* displaying them on some static web page with internal company-wide access

* providing diagnosis in simple English so most people can figure out
the issue if there's any "fails"

* maybe even pull in the output of SPF especially if relevant to
remediation ("Please add $mass_spammer to you SPF")

I'm more than happy to keep stored in the filesystem, as opposed to in a
database at this point.

How are you dealing? What other applications are worthwhile to explore?


PS: we need to get back to using talk@ for these routine day-to-day
questions. talk@ was once an arena for these questions, but I think many
have dropped this habit since many are concerned with asking "dumb
questions" and some prospective employer saying "what a stupid question".

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