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Re: [dmarc-ietf] Thoughts on choosing N

John Levine <johnl@taugh.com> Mon, 15 April 2024 16:34 UTC

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From: John Levine <johnl@taugh.com>
To: dmarc@ietf.org
Cc: vesely@tana.it
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Subject: Re: [dmarc-ietf] Thoughts on choosing N
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It appears that Alessandro Vesely  <vesely@tana.it> said:
>8 is not needed and not justified.  A mail site using 8 labels would have 
>troubles with the RFC 7489 version, which uses the PSL.  They'd have to ask for 
>PSL upgrades, right?

No, they would not. They might ask to have their pseudo-TLDs added to
the PSL but there's a process for that and it is definitely not our
problem.

>Now, we can relax our ambition to be PSL-free and state N=max number of labels 
>of public suffixes used by mail.  Or we could put N in an IANA registry that 
>can be updated by expert review.  Such methods allow to have N low enough, yet 
>upgradable and equal for all (compliant) implementations.

That is a great deal of complication for no benefit whatever.

I'm with Scott, pick a number, 5, 8, whatever, and be done with it.

R's,
John

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