Subject: [dmarc-ietf] PSL integration

From: Douglas Foster <[email-masked]>
Date: Sun, 27 Mar 2022 20:50:46 -0400

I have been giving some thought to the limitations of our current design,
and they are substantial, because we have been pursuing a solution based on
replacing the PSL, rather than a solution which integrates and improves on
the PSL.

We have a near-term problem, because our current solution asks evaluators
to abandon the information-rich to replace it with the information vacuum
of the DNS.    While that vacuum may be filled over time, the current draft
has further aggravated the problem by specifying an indicator token which
was chosen to "confuse so that people will not use it."   Additionally, the
new algorithm is significantly more complex than the RFC 7489
specification, while producing inferior results.
If the intent is to kill DMARC by publishing a standard that no one uses,
that effort is close to success.

Our legitimate goal is to displace the PSL with information published by
domain owners, as that information becomes available.   The solution will
need to guide evaluators to check the DNS for DMARCbis information and
indicators, while falling back to the PSL when the DMARCbis information is
not present, while supplementing both of them with local policy as
desired.

We need design work around the process an evaluator uses to choose between
the new system and the PSL, as well as the information that DMARCbis
communicates.   I have begun working on ideas, but wanted to get the
problem statement aired so that everyone could begin thinking about the
problem.

Doug Foster