Network Working Group                                          G. Huston
Internet-Draft                                                     APNIC
Intended status: Informational                                   P. Koch
Expires: March 14, 2017                                         DENIC eG
                                                               A. Durand
                                                               W. Kumari
                                                      September 10, 2016

Problem Statement for the Reservation of Special-Use Domain Names using


   The dominant protocol for name resolution on the Internet is the
   Domain Name System (DNS).  However, other protocols exist that are
   fundamentally different from the DNS, and may or may not share the
   same namespace.

   When an end-user triggers resolution of a name on a system that
   supports multiple, different protocols or resolution mechanisms, it
   is desirable that the protocol used is unambiguous, and that requests
   intended for one protocol are not inadvertently answered using
   another protocol.

   RFC 6761 introduced a framework by which a particular domain name
   could be acknowledged as being special.  Various challenges have
   become apparent with this application of the guidance provided in RFC
   6761.  This document focuses solely on documenting the specific
   challenges created by RFC 6761 in the form of a problem statement in
   order to facilitate further discussions of potential solutions.  In
   particular, it refrains from proposing or promoting any solution.
   Also, the current document does not focus on other general issues
   related to the use of special use domain names.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at

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   This Internet-Draft will expire on March 14, 2017.

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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction: DNS, Name Space or Name Spaces, Name Resolution
       Protocols . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  IETF RFC6761 Special Names  . . . . . . . . . . . . . . . . .   4
   3.  Issues with RFC 6761 process  . . . . . . . . . . . . . . . .   4
   4.  Issues with the RFC6761 registry  . . . . . . . . . . . . . .   5
   5.  Issues Around the IETF Evaluation of Candidate Strings  . . .   6
   6.  Other Issues Related to RFC6761 . . . . . . . . . . . . . . .   6
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   7
     10.2.  Informative References . . . . . . . . . . . . . . . . .   7
   Appendix A.  Editorial Notes  . . . . . . . . . . . . . . . . . .   8
     A.1.  Venue . . . . . . . . . . . . . . . . . . . . . . . . . .   8
     A.2.  Change History  . . . . . . . . . . . . . . . . . . . . .   8
       A.2.1.  draft-adpkja-special-names-problem-00 . . . . . . . .   8
   Appendix B.  Change history . . . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

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1.  Introduction: DNS, Name Space or Name Spaces, Name Resolution

   For a very long time, "DNS" and "the name space" have been perceived
   as the same thing.  However, this has not always been the case; in
   the past, other name resolution protocols (such as NIS, NIS+, host
   files, UUCP addresses, and others) were popular.  Most of those have
   been obsoleted by the DNS in the late 1990s.  More information on the
   history of names and namespaces can be found in

   More recently, new name resolution protocols have been proposed, each
   addressing a particular need or a particular community.  For example,
   the DONA handle system [DONA] has been used by parts of the
   publication industry.  The Apple "Bonjour" set of protocols, inspired
   by what was available on Appletalk networks, was developed to perform
   automatic name resolution on a local IP network.  The TOR project is
   using the onion system to obfuscate communications, the GNU Name
   System (GNS) system is using block chains to build a decentralized
   name system to offer "privacy and censorship resistance".  Many more
   name resolution protocols have been proposed.

   These alternate name resolution protocols do not exist in a vacuum.
   Application developers have expressed a strong desire to build their
   software to function in any of those universes with minimal changes.
   In order to do so, the software has to deterministically recognize
   what kind of name it is dealing with and associate it with the
   corresponding name resolution protocol.  An algorithmic solution
   frequently chosen by application developers consists simply in using
   a special tag padded at the end of a name to indicate an alternate
   name resolution method.  For example, if a name ends in .local, the
   software uses the Apple Bonjour protocol based on multicast DNS; if
   the name ends in .onion, it uses the TOR protocol; if the name ends
   in .gnu, it uses the GNS protocol, and so on.  One noteworthy
   exception to this approach is the DONA system that has its own
   interoperability mechanism with the DNS.  Another noteworthy
   exception is the Frogans technology [FROGANS] which name space uses
   the character '*' to separate network names from site names and allow
   any character, including dots on either side of the '*'.

   A result of the above is that a number of applications have been
   developed (and massively distributed) that have encoded their
   favorite "tag" as a DNS TLD in a free-for-all, beginning their
   existence by squatting on that DNS space; .local, .gnu, .onion
   started out like that.

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2.  IETF RFC6761 Special Names

   The IETF used a provision from the IETF/ICANN MoU [RFC2860] section
   4.3 that says that "(a) assignments of domain names for technical
   uses" is to be considered the purview of IETF (outside of the scope
   of ICANN) in order to create a way to reserve such names in a list of
   "special names".  That process is documented in [RFC6761] (which,
   however, does not directly refer the IETF/ICANN MoU).  The [RFC6761]
   process was first applied for .local, and the more recently for

   When the [RFC6761] process was put in place, many thought it would
   only be used a handful of times.  However, a large number of
   applications have since been made to the IETF.  The .onion evaluation
   took almost a year and has started a massive (and often heated)
   discussion in the IETF.

   [RFC6761] has a number of issues.  This document groups those issues
   in several categories.

3.  Issues with RFC 6761 process

   a.  [RFC6761] does not mention if the protocol using the reserved
       name should be published as an RFC document.

          Most applications have, so far, come from outside
          organizations, and the described protocols that have not been
          developed by the IETF.

   b.  [RFC6761] does not provide clear enough directions as to which
       group of people is responsible for carrying out the evaluation
       for inclusion in the registry.

          There are ambiguities and no formal criteria on how the IETF
          can (or even whether the IETF should) evaluate the merits of
          applicants to [RFC6761] reservations.

   c.  The "seven questions" of [RFC6761] are inadequate for evaluating

          Section 5 of [RFC6761] describes seven questions to be
          answered by an applicant for [RFC6761] status.  However,
          running this process for the .onion application showed that
          those seven questions are inadequate for making the
          determination of whether a particular string qualifies for
          [RFC6761] treatment.

   d.  Some organizations may want to experiment with a reserved name.

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          They may or may not be ready (or willing) to go through a
          cumbersome process and find [RFC6761] too difficult to deal
          with.  They would like a much simpler registration process,
          with limited or no burden to apply.

   e.  The [RFC6761] process could be abused.

          In particular, the process can be abused to reserve a specific
          string within an existing suffix (or set of suffixes using
          wildcards) not under the control of IETF.

   f.  [RFC6761] does not have provision for subsequent management of
       the registry, such as updates, deletions of entries, etc...

4.  Issues with the RFC6761 registry

   a.  The [RFC6761] registry lacks sufficient documentation supporting
       a registration.

          The registry may point to the RFC creating the reservation,
          but not to the supporting materials.

   b.  The [RFC6761] registry lacks clear directions for applications to
       select which name resolution method to use upon seeing the
       special name.

          In particular, it lists the reserved names but does not
          include direct guidance, neither in free text form nor in
          machine-readable instructions, for any of the seven audiences.
          Instead, the registry relies on a reference for each entry to
          the document that requested its insertion.  Such documents
          could be difficult to read for many readers; for example,
          [RFC6762] is a 70-page protocol specification which is not an
          effective way to set expectations of non-technical end-users.

   c.  Reserving a string in [RFC6761] does not guarantee queries will
       not leak in the DNS.

          The applicants for [RFC6761] status cannot be guaranteed that
          leakage will not occur and will need to take this into account
          in their protocol design.

   d.  The intended usage or protocol for which the [RFC6761]
       reservation is made may or may not be successful.

          In the case of failure of adoption, the reserved string would
          be wasted.

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5.  Issues Around the IETF Evaluation of Candidate Strings

   a.  The IETF does not have a formal process to evaluate candidate
       strings for issues such as trademark infringement and name

          This leads to concerns about liability risks incurred by
          adding a particular string to the [RFC6761] registry.

   b.  Submitting the application to IETF last call does not guarantee
       such issues will be always caught.

          [RFC7788] describing the "home networking control protocol"
          was recently published.  That document includes text
          instructing devices to use names terminating by default with
          the .home suffix.  [RFC7788] did not reference [RFC6761]
          anywhere and had no IANA sections about this reservation.  It
          was published without anyone noticing this during the entire
          review process.  The issue was caught after the publication,
          and an errata was published.

6.  Other Issues Related to RFC6761

   [RFC6761] does not include a mechanism to collaborate with ICANN.

      The current round of ICANN gTLD (described at [NEW-GTLD]) is, as
      the time of this writing, closed to new applications.  It is,
      however, not yet completed.  Some applications are still under
      consideration.  There is a risk that, without proper collaboration
      between the IETF and ICANN, a new entry in the [RFC6761] registry
      could conflict with one of those applications still under review.
      It should also be noted that discussions have started about
      forming the next round of ICANN gTLDs, thus this issue will not go
      away at the conclusion of the current gTLD round.

7.  Security Considerations

   This document aims to provide a problem statement that will inform
   future work.  While security and privacy are fundamental
   considerations, this document expects that future work will include
   such analysis, and hence no attempt is made to do so here.  See
   [SAC-057] for further considerations.

   Reserving names has been presented as a way to prevent leakage into
   the DNS.  However, instructing resolvers to not forward the queries
   (and/or by instructing authoritative servers not to respond) is not a
   guarantee that such leakage will be prevented.  The security (or

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   privacy) of an application MUST NOT rely on names not being exposed
   to the Internet DNS resolution system.

8.  IANA Considerations

   This document has no IANA actions.

9.  Acknowledgements

   Thanks to Paul Hoffman for a large amount of editing.

10.  References

10.1.  Normative References

              IANA, "Special-Use Domain Names", 2016,

   [RFC2860]  Carpenter, B., Baker, F., and M. Roberts, "Memorandum of
              Understanding Concerning the Technical Work of the
              Internet Assigned Numbers Authority", RFC 2860,
              DOI 10.17487/RFC2860, June 2000,

   [RFC6761]  Cheshire, S. and M. Krochmal, "Special-Use Domain Names",
              RFC 6761, DOI 10.17487/RFC6761, February 2013,

   [RFC6762]  Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
              DOI 10.17487/RFC6762, February 2013,

   [RFC7788]  Stenberg, M., Barth, S., and P. Pfister, "Home Networking
              Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April
              2016, <>.

10.2.  Informative References

   [DONA]     DONA, "DONA Foundation", June 2016,

   [FROGANS]  Frogans Technology, "Frogans Technology", June 2016,

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              ICANN, "gTLD Application Guidebook", June 2012,

   [HUSTON]   Huston, G., "What's in a Name?", December 2015,

              Lewis, E., "Domain Names", draft-lewis-domain-names-03
              (work in progress), June 2016.

              ICANN, "New Generic Top-Level Domains", 2016,

   [SAC-057]  ICANN Security and Stability Advisory Committee, "SSAC
              Advisory on Internal Name Certificates", March 2013,

Appendix A.  Editorial Notes

   This section (and sub-sections) to be removed prior to publication.

A.1.  Venue

   An appropriate forum for discussion of this draft is, for now, the

A.2.  Change History

A.2.1.  draft-adpkja-special-names-problem-00

   Initial draft circulated for comment.

Appendix B.  Change history

   [ RFC Editor: Please remove this section before publication]

   -06 to -05:

   o  Clarify the sole focus of this draft is to document problems
      created by RFC6761, and not the larger issue of NON-DNS TLDs.

   o  Split issue lists and rewrite some for clarity.

   -05 to -04:

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   o  Added two issues to the issue list: market failure and
      experimental use.

   -04 to -03:

   o  Minor edits to correct grammar, clarify that the current ICANN
      gTLD round is closed.

   -03 to -02:

   o  Significant readability changes to focus the discussion.

   -01 to -02:

   o  A very large number of readability / grammar / reference fixes
      from Paul Hoffman.

   -00 to -01:

   o  Significant readability changes.


   o  Initial draft circulated for comment.

Authors' Addresses

   Geoff Huston


   Peter Koch
   Kaiserstrasse 75-77
   Frankfurt  60329


   Alain Durand


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   Warren Kumari


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