Re: [dmarc-ietf] Fwd: I-D Action: draft-ietf-dmarc-psd-10.txt

[Barry Leiba <[e-mail]>]

OK, here's my proposal; please let me know what you think:

— Abstract —

OLD
   DMARC (Domain-based Message Authentication, Reporting, and
   Conformance) is a scalable mechanism by which a mail-originating
   organization can express domain-level policies and preferences for
   message validation, disposition, and reporting, that a mail-receiving
   organization can use to improve mail handling.  The design of DMARC
   presumes that domain names represent either nodes in the tree below
   which registrations occur, or nodes where registrations have
   occurred; it does not permit a domain name to have both of these
   properties simultaneously.  Since its deployment in 2015, use of
   DMARC has shown a clear need for the ability to express policy for
   these domains as well.

   Domains at which registrations can occur are referred to as Public
   Suffix Domains (PSDs).  This document describes an extension to DMARC
   to enable DMARC functionality for PSDs.

   This document also seeks to address implementations that consider a
   domain on a public Suffix list to be ineligible for DMARC
   enforcement.

NEW
   DMARC (Domain-based Message Authentication, Reporting, and
   Conformance) is a scalable mechanism by which a mail-originating
   organization can express domain-level policies and preferences for
   message validation, disposition, and reporting, that a mail-receiving
   organization can use to improve mail handling.

   DMARC uses a Public Suffix List (PSL) to determine what part of a
   domain name is the Public Suffix Domain (PSD), below which
   organizational domain names are created.  DMARC allows organizational
   domains to specify policies that apply to their subdomains, but it
   does not give that flexibility to PSDs.

   This document describes an extension to DMARC to fully enable DMARC
   functionality for PSDs.  This document also addresses implementations
   that consider a domain on a public Suffix list to be ineligible for
   DMARC enforcement.


— Section 1 —

OLD
   DMARC as specified presumes that domain names present in a PSL are
   not organizational domains and thus not subject to DMARC processing;
   domains are either organizational domains, sub-domains of
   organizational domains, or listed on a PSL.  For domains listed in a
   PSL, i.e., TLDs and domains that exist between TLDs and organization
   level domains, policy can only be published for the exact domain.  No
   method is available for these domains to express policy or receive
   feedback reporting for sub-domains.  This missing method allows for
   the abuse of non-existent organizational-level domains and prevents
   identification of domain abuse in email.

NEW
   DMARC as specified presumes that domain names present in a Public
   Suffix List (PSL) — Public Suffix Domains (PSDs) — are not
   organizational domains and are thus not subject to DMARC processing.
   In DMARC, domains fall into one of three categories: organizational
   domains, sub-domains of organizational domains, or PSDs.  For PSDs,
   policy can only be published for the exact domain: no mechanism is
   available for PSDs to express policy or receive feedback reporting
   for sub-domains.  The lack of such a mechanism allows for the abuse
   of non-existent organizational-level domains and hampers
   identification of domain abuse in email.

— Section 1.1 —

OLD
   As an example, imagine a country code TLD (ccTLD) which has public
   subdomains for government and commercial use (".gov.example" and
   ".com.example").  A PSL whose maintainer is aware of this country's
   domain structurewould include entries for both of these in the PSL,
   indicating that they are PSDs below which registrations can occur.
   Suppose further that there exists a domain "tax.gov.example",
   registered within ".gov.example", that is responsible for taxation in
   this imagined country.

NEW
   As an example, imagine a Top-Level Domain (TLD), ".example", that has
   public subdomains for government and commercial use (".gov.example"
   and ".com.example").  A PSL whose maintainer is aware of this TLD’s
   domain structure would include entries for both of these in the PSL,
   indicating that they are PSDs below which organizational domains can
   be registered.  Suppose further that there exists a legitimate domain
   called "tax.gov.example", registered within ".gov.example".



OLD
   This DMARC record provides policy and a reporting destination for
   mail sent from @gov.example.  However, due to DMARC's current method
   of discovering and applying policy at the organizational domain
   level, the non-existent organizational domain of @t4x.gov.example
   does not and cannot fall under a DMARC policy.

NEW
   This DMARC record provides policy and a reporting destination for
   mail sent from @gov.example.  Similarly, "tax.gov.example" will have
   a DMARC record that specifies policy for mail sent from addresses
   @tax.gov.example.  However, due to DMARC's current method of
   discovering and applying policy at the organizational domain
   level, the non-existent organizational domain of @t4x.gov.example
   does not and cannot fall under a DMARC policy.


-- 
Barry

On Mon, Feb 22, 2021 at 9:33 AM Barry Leiba <[e-mail]> wrote:
>
> >> > I'm at a loss to understand what's confusing.  I'm not convinced that "registrations" in the
> >> > context of domain names is unclear to a reader familiar with this space.
> >>
> >> I am absolutely convinced that it is.  Think of people in M3AAWG, for
> >> whom this is very relevant.  Many of them don't know much about
> >> registries, registrars, and such, and in general, the average reader
> >> won't understand the difference, from a "registration" standpoint,
> >> between facebook.com (which is registered) and "www.facebook.com"
> >> (which is not).  To the average reader, "facebook.com" is registered
> >> under com, and "www.facebook.com" is registered under facebook.  And
> >> the ones who don't think that will likely not understand why we can't
> >> just talk about second-level domains and be done with it.
> >
> > Actually that's a community that I would expect to know exactly what all those terms mean and
> > how they are all related.
>
> There clearly are some in that community who do.  But there are many
> there who don't.  This stuff is more esoteric than those of us who are
> in the middle of it often realize.
>
> > I think the use of "registered" seems to be the source of some of this confusion.
>
> Yes, exactly.
>
> > To work with the example you gave here, I agree that "facebook.com" is registered (under "com"), but
> > disagree that "www.facebook.com" is registered at all;
>
> Right, of course it's not.  I didn't say that it is: I said that
> people who don't fully understand this stuff *think* it is, and that's
> the part that the text isn't making clear.
>
> > To my mind, "register" involves a specific transaction, sometimes involving money, with whoever gates
> > access to make those delegations.
>
> And that's what we need to explain better in the Introduction.
>
> > How's this?:
> >
> >    DMARC (Domain-based Message Authentication, Reporting, and
> >    Conformance) is a scalable mechanism by which a mail-originating
> >    organization can express domain-level policies and preferences for
> >    message validation, disposition, and reporting, that a mail-receiving
> >    organization can use to improve mail handling.
> >
> >    Within the Domain Name System (DNS) on the public Internet, which is
> >    organized as a tree, some nodes of that tree are reserved for use by
> >    registrars, who delegate sub-trees to other operators on request.  DMARC currently
> >    permits expression of policy only for such sub-trees.  There is a marked desire to
> >    be able to express policy for the reserved nodes as well.  This document
> >    describes an experimental extension to DMARC to add that capability.
> >
> > If we like that as a replacement Abstract, I'll carry on and propose a revision to the Introduction.
>
> I don't think that really explains it properly either -- I think with
> the above text, it's less confusing, but also not correct, or at least
> not really indicative of what the document is proposing.
>
> I don't have time today, but give me a couple of days to work on the
> Abstract and the Introduction/Example, and I'll propose some specific
> text that we can try out.
>
> Barry
>
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