[dmarc-ietf] Tree Jump method - reporting targeting

[Douglas Foster <[e-mail]>]

While the PSL can determine an organizational domain from any From address,
the Tree Jump method only works if there is a single-subdomain DMARC policy
to contain the orgname=FQDN token.    This means that we would need to
encourage domain owners to publish policies on each domain that sends mail,
something that is not required now.

But if I understand the specification correctly, every DMARC policy serves
to partition the reporting scope, with results for subdomains sent to the
subdomain target, and results for the organizational domain sent to the
organizational domain target after excluding the separately-reported
subdomain results.    Domain owners may be reluctant to publish
single-domain policies because they do not want this partitioning.

Consequently, it seems desirable to have a reporting preference indicator
for DMARC policies on subdomains:    ReportTargets=(self, org, both).
 When ReportTargets=org, the rua=address could be omitted, since the rua
destination will be taken from the organizational domain policy.
 ReportTargets=org would allow the domain owners to publish
single-subdomain policies without altering the reporting structure, and
without replicating a specific address in multiple policy records.