Re: [dmarc-ietf] Comment on draft-ietf-dmarc-psd

Scott Kitterman <sklist@kitterman.com> Sat, 07 December 2019 20:11 UTC

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From: Scott Kitterman <sklist@kitterman.com>
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Date: Sat, 07 Dec 2019 15:11:13 -0500
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Subject: Re: [dmarc-ietf] Comment on draft-ietf-dmarc-psd
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On Wednesday, December 4, 2019 8:04:00 PM EST Brandon Long wrote:
> On Wed, Dec 4, 2019 at 10:01 AM Kurt Andersen (b) <kboth@drkurt.com> wrote:
> > On Wed, Dec 4, 2019 at 2:39 AM Alessandro Vesely <vesely@tana.it> wrote:
> >> > Rather, it's primed as a possibly useful data collection exercise.
> >> 
> >> Kurt also talked about reporting some findings.  I'm embarrassed, I have
> >> no
> >> idea what I, as a receiver, should report.  What data should I, and other
> >> receivers collect?
> > 
> > I was thinking of something along the line of what was assembled for RFC
> > 6686. In this case it would be something like the quantity of messages
> > which were assessed against the LPSD record and their disposition compared
> > to the number of messages dispositioned at the org level. Something to
> > answer Dave's concern about "too much additional work" for not enough
> > benefit.
> 
> Remind me again the the additional work is that might be too much?  Isn't
> it just another DNS lookup for the org domain -1... of which there are
> maybe a couple thousand and easily cacheable?
> 
> This seems way less than say the additional work for ARC.

It's slightly more.  There's also a check to see if a LPSD (org -1) is a PSD 
DMARC participant.  Exactly how to document that is the major unresolved 
question that we should evaluate experimentally.  It might be one of three 
things:

1.  A registry that is occasionally updated and consumed locally.
2.  A DNS RBL type service lookup.
3.  An exended PSL.

Options 2 and 3 both have a second additional lookup.  Personally, I like 
option 1, but there's no consensus about this.  There are working versions of 
all three available from psddmarc.org for testing.

Scott K