Technical Summary
This document updates RFC 4871, DomainKeys Identified Mail (DKIM)
Signatures. Specifically the document clarifies the nature, roles
and relationship of the two DKIM identifier tag values that are
candidates for payload delivery to a receiving processing
module. The Update is in the style of an errata entry.
Working Group Summary
This document arose from an errata report against RFC 4871, and
from attempts to address the issue raised, which required
clarification of some terminology. After some discussion, it was
clear that the working group is divided as to how extensive the
clarification needs to be, with a significant majority opting for
the more extensive version represented here. In a spirit of
compromise and a desire for progress, the working group agreed to
some changes to the text that make it acceptable to most of the
participants.
RFC 4871 was published two years ago, and since then, the
collective understanding of the role of DKIM has improved based on
deployment experience and work on the other DKIM WG drafts (Author
Domain Signing Practices; Service Overview; Development, Deployment
and Operations). Since it is not absolutely clear that the
clarifications completely match the intent at the time when
RFC 4871 was published (when the role of DKIM was less well
understood), they are published as an RFC updating RFC 4871 instead
of an RFC Editor errata, to ensure that they go through the normal
IETF consensus process.
Document Quality
There is a significant level of deployment of DKIM, as documented
by RFC 4871. In fact, the existing deployment and good
interoperability is what makes a part of the working group unsure
that a clarification of this nature is necessary. Nevertheless,
discussion within the working group made it clear to many that
there is a significant amount of disagreement as to what was meant
in some less-used areas of RFC 4871. The working group believes
that these updates will clarify the terminology and improve chances
of interoperability among implementations that use those features.
Personnel
The document shepherd is Barry Leiba, and the responsible area
director is Pasi Eronen.