To avoid munging, MLMs have a double problem: (1) the evaluator must find an alternative to DMARC for concluding that the message is "not untrusted", and (2) the MLM must know that this trust has been granted.
If (2) is known for some recipients but not others, the MLM must be able to make munging conditional on the destination domain. Given the perceived intransigence of AOL, having (2) known for all recipients is not expected. Based on previous conversations, MLMs are not willing to perform conditional munging, so munging cannot be prevented if any subscriber domain publishes a policy other than "none". Unminging has the advantage of being a local policy implementation with potentially no dependency on the MLM. But unmunging must be reversed if any messages are re-forwarded. The technical challenges of knowing when to re-mung seem significant. DF On Wed, Aug 10, 2022, 12:14 AM Murray S. Kucherawy <[email protected]> wrote: > On Tue, Aug 9, 2022 at 2:01 AM Alessandro Vesely <[email protected]> wrote: > >> > Because there are more ways for a forwarder to change a message than >> you or >> > I can describe. >> >> That critic applies to my draft, not to unmunging in general. The only >> change we care about here is the From: field. While there are many ways >> to >> munge it, there is a simple way to restore it: >> >> IF message is dmarc=pass AND From: domain belongs to $MAILING_LIST_SET >> IF Author: is set >> RENAME From: Munged-From: >> COPY Author: From: >> >> Et voilà! >> > > This only works when that second "if" is true. Of all the emails in this > particular thread, only yours have it set. > > So now, perhaps a hyperbolic question, but: If we were to adopt and > publish draft-crocker-dmarc-author, what's the likelihood that we could get > all MUAs to start adding it? And then, what's the likelihood that it will > remain pristine in the future? > > -MSK > _______________________________________________ > dmarc mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/dmarc >
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