Re: [dmarc-ietf] Abolishing DMARC policy quarantine

Hello,

(I repeat what was said here, just in case)

As it was pointed out, p=quarantine; pct=0; is the same as p=none; and p=reject; ptc=0; is the same as p=quarantine;
pct=100, therefore p=quarantine; pct=0 is not the same as p=reject; pct=0 currently, per 
https://tools.ietf.org/html/rfc7489#section-6.6.4 (RFC DMARC, Section Message Sampling)

And then, for p=none or any equivalent form of it, there is no need or established practice for mungling, while for
p=reject; pct=0, or any equivalent form of it, there is mungling.

This is the current specification.  I proposed on this regard in fact two things:
- specifying that p=quarantine; pct=0 (email from 10th May to dmarc@ietf) the MLM does mungling
- abolishing policy quarantine

That is: p=reject; pct=0 gets almost the same as p=none, except that there is recommendatiton for MLM to mungle From:.

Regards
  Дилян
On Wed, 2019-07-24 at 19:36 +0300, Vladimir Dubrovin wrote:
> 
> Hello Murray,
> 
> Yes, rewriting depends on policy. Look at From: headers for this mailing list (dmarc@ietf.org), you can see it only munges From address for domain with strict DMARC policy (if RFC5322.From domain publishes "quarantine" or "reject" policy). This is very common behavior, it can also be seen in Google Groups.
> 
> But, as it was correctly pointed by Dilyan Palauzov, there should be no difference between "p=quarantine;pct=0" and "p=reject;pct=0" for valid DMARC Mail Receiver implementation, so "p=reject;pct=0" can probably be used instead. 
> 
> 24.07.2019 18:27, Murray S. Kucherawy пишет:
> > On Fri, Jun 14, 2019 at 12:25 PM Vladimir Dubrovin <dubrovin=40corp.mail.ru@dmarc.ietf.org> wrote:
> > > Nope, I mean 2 different things. 
> > > 
> > > 1. Why quarantine is useful (with pct=0).  
> > > 
> > > For example this mailing list (dmarc@ietf.org) performs >From rewrite (aka From munging), e.g. dubrovin@corp.mail.ru is replaced with dubrovin=40corp.mail.ru@dmarc.ietf.org.                 It's because corp.mail.ru has a strict DMARC policy (reject). dotzero@gmail.com is not overwritten, because gmail.com has p=none and ietf.org only overwrites From only for domains with "quarantine" and "reject" policies. It's quite common behavior.
> > > 
> > > If you are implementing DMARC for a new domain (let's say example.org), you usually start with "p=none". With p=none you receive reports for failed DMARC for different lists, like ietf.org. Before switching to stronger policy (p=reject), you may want to know which mailing list will still fail DMARC, and which lists perform From munging and, as a result, do not fail DMARC. For this purpose, before switching to "p=reject" it's useful to switch to "p=quarantine;pct=0". After this, you will only see mailing lists without From munging in DMARC reports.
> > > 
> > 
> > I'm confused; is this claiming that those rewrites happen by virtue of the fact that "p=quarantine" is the published policy?  Seems to me that rewriting will happen irrespective of what the published policy is for the From domain.
> > 
> > Or is it the case that this changes the content of the aggregate reports in a way you find meaningful?
> > 
> > -MSK
> > 
> > 
> > _______________________________________________
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> > dmarc@ietf.org
> > https://www.ietf.org/mailman/listinfo/dmarc
> 
> 
> -- 
> Vladimir Dubrovin 
> @ mail.ru