Re: [dmarc-ietf] what to document about the tree walk

[Alessandro Vesely <[e-mail]>]

On Wed 13/Jul/2022 17:56:08 +0200 Scott Kitterman wrote:
> On July 13, 2022 3:10:38 PM UTC, "Murray S. Kucherawy" <[e-mail]> wrote:
>> Once again, participating only:
>> On Wed, Jul 13, 2022 at 3:43 AM Douglas Foster wrote:
>>> [...]
>>
>>> 3) The critical question is whether we can treat the PSL as replaced
>>> without obtaining the markers first.   On this issue, John and I have a
>>> different assessment of the risk.   I can accept a solution which lays out
>>> the assumptions and risks to the evaluator, and lets them decide what to
>>> do.  This is what sections 4.7. and 4.8 in my text from Sunday night
>>> attempted to do.
>>
>> My suggestion would be that if we are going to offer a choice, there should
>> be some eventual path toward convergence rather than an open-ended period
>> of people doing either.  Otherwise, the PSL will be a part of DMARC for far
>> longer than we'd like.
> 
> I think a choice within DMARCbis is a bad idea.  Effectively the choice exists.  Evaluators will have the choice to stay with an RFC 7489 design or to upgrade to DMARCbis.


The incentive to upgrade is not clear.  DMARC filters can run based on 
an obsolete version of the PSL with no inconvenience, for a different 
flavor of "upgrade".  Indeed, according to John's figures, we could 
have done without any psd= tag.

Doug's idea of checking the results is a means to draw the attention 
of operators on both the PSL version they use and its agreement with 
the DNS at large.  New implementations could be encouraged to track 
the differences and produce some kind of report about them.  IME, 
although running a very small mail site, it does happen to hit some 
PSL entry, a fact which I realized by chance —browsing the logs— so I 
cannot tell figures.


> We can't get rid of the PSL without getting rid of the PSL.
> 
> There's no way to constrain it within the document.  If we have a 'choice', we are essentially signing up the IETF to a future effort to produce an update to actually get rid of it.


Right, that would be the Internet Standard.


Best
Ale
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