Skip to main content

Concluded WG SPF Update (spfbis)

Note: The data for concluded WGs is occasionally incorrect.

WG Name SPF Update
Acronym spfbis
Area Applications Area (app)
State Concluded
Charter charter-ietf-spfbis-01 Approved
Document dependencies
Additional resources Issue tracker, Wiki
Personnel Chairs Andrew Sullivan, S Moonesamy
Area Director Pete Resnick
Mailing list Address
To subscribe

Final Charter for Working Group

  The Sender Policy Framework (SPF, RFC4408) specifies the publication
  of a DNS record which states that a listed IP address is authorized
  to send mail on behalf of the listing domain name's owner.  SMTP
  servers extract the domain name in the SMTP "MAIL FROM" or "HELO"
  command for confirming this authorization.  The protocol has had
  Experimental status for some years and has become widely deployed.
  This working group will summarize the result of the experiment and
  revise the specification, based on deployment experience and listed
  errata, and will seek Standards Track status for the protocol.

  The MARID working group considered two specifications for
  publication of email-sending authorization:  Sender-ID, which
  eventually became RFC4405, RFC4406 and RFC4407, and SPF, which
  eventually became RFC4408, all in the end published under
  Experimental status.  By using IP addresses, both protocols specify
  authorization in terms of path, though unlike SPF, Sender-ID uses
  domain names found in the header of the message rather than the

  The two protocols rely on the same policy publication mechanism,
  namely a specific TXT resource record in the DNS.  This creates a
  basic ambiguity about the interpretation of any specific instance of
  the TXT record.  Because of this, there were concerns about
  conflicts between the two in concurrent operation.  The IESG note
  prepended to RFC 4405 through RFC 4408 defined an experiment with
  SPF and Sender-ID, and invited an expression of community consensus
  in the period following the publication of those specifications.

  Both technologies initially enjoyed widespread deployment.  Since
  that time, broad SPF use has continued, whereas use of Sender-ID has
  slackened.  Furthermore, SPF's linkage to the envelope (as opposed
  to Sender-ID's linkage to identifiers in the message content) has
  proven sufficient among operators.

  Formation of the SPF Update Working Group is predicated on three

  1. The SPF/Sender-ID experiment has concluded.

  2. SPF has been a qualified success, warranting further development.

  3. Sender-ID has had less success, and no further development is justified.

  The working group will produce a document describing the course of
  the SPF/Sender-ID experiment, thus bringing that experiment to a
  formal conclusion.  The group will complete additional work on SPF
  (described below), but will not complete additional work on the
  Sender-ID specification.

  Changes to the SPF specification will be limited to the correction
  of errors, removal of unused features, addition of any enhancements
  that have already gained widespread support, and addition of
  clarifying language.

  Specifically out-of-scope for this working group:

  * Revisiting past technical arguments where consensus was reached in
    the MARID working group, except where review is reasonably
    warranted based on operational experience.

  * Discussion of the merits of SPF.

  * Discussion of the merits of Sender-ID in preference to SPF.

  * Extensions to the SPF protocols.

  * Removal of existing features that are in current use.

  Discussion of extensions to the SPF protocols or removal of
  existing features shall only be discussed after completion of
  current charter items in anticipation of rechartering the working

  An initial draft of an updated SPF specification document is
  draft-kitterman-4408bis. The working group may choose to use this
  document as a basis for their specification.

Done milestones

Date Milestone Associated documents
Done A standards track document defining SPF, based on RFC4408 and as amended above, to the IESG for publication.
Done A document describing the SPF/Sender-ID experiment and its conclusions to the IESG for publication.