[dmarc-ietf] More rethinking on DMARC for PSDs

Alessandro Vesely <vesely@tana.it> Wed, 10 April 2019 16:55 UTC

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From: Alessandro Vesely <vesely@tana.it>
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Subject: [dmarc-ietf] More rethinking on DMARC for PSDs
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I changed the subject to make it clear that this is not about mail filtering in
general.  It is about Scott's draft.


On Mon 08/Apr/2019 02:50:44 +0200 John Levine wrote:
> 
> A decent spam filter will treat a nonexistent From: domain or envelope
> bounce address as extremely suspicious and send the message into spam
> folder purgatory.  If someone's filters aren't doing that, it is
> unlikely that they're paying much if any attention to DMARC, and no
> amount of fiddling with DMARC will make any difference.
> 
> My mail server rejects anything with a non-existent bounce address at
> SMTP time and I don't think it's ever rejected anything my users would
> want.


Me too.  However, I don't reject nxdomain in From:.  I have the option, but I
disabled it because some mailing lists have (had?) authors with addresses like
johndoe@NOSPAMexample.com.

That said, rethinking boils down to consider if it would suffice to look up the
PSD's _dmarc record only in case of non-existing domains.  Existing domains can
be forced to publish adequate DMARC records by forging a suitable PSD's policy.
 That way, old-fashioned mailing lists can continue to use picturesque From:'s
as long as they are based on traditional TLDs (assuming .com won't publish a
strict DMARC policy.)  And no central repository.


jm2c
Ale
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