A Top-level Domain for Private Use
draft-davies-internal-tld-00

Network Working Group                                          K. Davies
Internet-Draft                                                      IANA
Intended status: Informational                             A. McConachie
Expires: 3 February 2025                                           ICANN
                                                           2 August 2024

                   A Top-level Domain for Private Use
                      draft-davies-internal-tld-00

Abstract

   This document describes the reservation of the ".internal" top-level
   domain for use in private applications.

Status of This Memo

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

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   This Internet-Draft will expire on 3 February 2025.

Copyright Notice

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Using the ".internal" Namespace . . . . . . . . . . . . . . .   2
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   6.  Additional Information  . . . . . . . . . . . . . . . . . . .   3
   7.  Informative References  . . . . . . . . . . . . . . . . . . .   4
   Notes (for removal before publication)  . . . . . . . . . . . . .   5
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   5
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   There are certain circumstances where private network operators may
   wish to use their own domain naming scheme that is not intended to be
   used or accessible by the global domain name system (DNS), such as
   within closed corporate or home networks.

   The "internal" top-level domain is reserved to provide this purpose
   in the DNS.  Such domains will not resolve in the global DNS, but can
   be configured within closed networks as the network operator sees
   fit.

   This reservation is intended for a similar purpose that private-use
   IP address ranges that are set aside (e.g.  [RFC1918]).

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   [BCP14] when, and only when, they appear in all capitals, as shown
   here.

   This document assumes familiarity with DNS terms; please see
   [BCP219].

3.  Using the ".internal" Namespace

   Network operators have been using different names for private-use DNS
   for many years.  This usage is uncoordinated and could result in
   incompatibilities or harm to Internet users.  For example, an
   organization might choose to use a name for this purpose that has not
   been assigned to them, that would later appear in the global DNS
   thereby causing name collisions and undefined behavior for users.

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   If an organization determines that they require a private-use DNS
   namespace, they should either use sub-domains of a global DNS name
   that is under their organizational and operational control, or use
   the "internal" top-level domain.  This document does not offer
   guidance on when a network operators should choose the "internal"
   top-level domain instead of a sub-domain of a global DNS name.  This
   decision will depend on multiple factors such as network design and
   organizational needs and is outside the scope of this publication.

   The "internal" namespace and the "alt" namespace [RFC9476] have been
   reserved for different purposes. "alt" has been reserved for non-DNS
   contexts, whereas "internal" is intended for use with the DNS
   protocol for in a private-DNS context.

4.  IANA Considerations

   The document requires no IANA actions.  For the reasons stated above,
   the "internal" top-level domain is reserved from being used in the
   global DNS and therefore MUST NOT appear in the DNS root zone.

5.  Security Considerations

   While the namespace is designated for private use, there is no
   guarantee that the names utilized in this namespace will not leak
   into the broader Internet.  Such usage may include appearance in log
   files, email headers, and the like.  Users, therefore, should not
   rely on the confidentiality of the "internal" namespace.

   Users should also not assume the appearance of such names is
   indicative of the true source of transmissions.  When diagnosing
   network issues, the appearance of such addresses must be interpreted
   with the associated context to ascertain the private network with
   which the name is being used.  A private-use name can never be used
   by itself to identify the origin of a communication.  It is entirely
   likely that many of the same names will be used for entirely
   differnet purposes on different networks connected to the Internet.

6.  Additional Information

   This reservation is the result of a community deliberation on this
   topic over many years, most notably [SAC113].  The SAC113 advisory
   recommended the establishment of a single top-level domain for
   private-use applications.  This top-level domain would not be
   delegated in the DNS root zone to ensure it is not resolvable in
   contexts outside of a private network.

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   ICANN implemented the recommendation of SAC113 through a process that
   first identified an appropriate selection procedure, and then
   conducted a selection process [IANA-Assessment] which determined
   "internal" was the best suited string given the requirement that a
   single string be selected for this purpose.  The ICANN Board of
   Directors subsequently adopted this recommendation and formally
   decided the reservation in July 2024.  [ICANN-Board-Resolution]

7.  Informative References

   [BCP14]    Best Current Practice 14,
              <https://www.rfc-editor.org/info/bcp14>.
              At the time of writing, this BCP comprises the following:

              Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

              Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [BCP219]   Best Current Practice 219,
              <https://www.rfc-editor.org/info/bcp219>.
              At the time of writing, this BCP comprises the following:

              Hoffman, P. and K. Fujiwara, "DNS Terminology", BCP 219,
              RFC 9499, DOI 10.17487/RFC9499, March 2024,
              <https://www.rfc-editor.org/info/rfc9499>.

   [IANA-Assessment]
              "Identification of a top-level domain for private use",
              January 2024, <https://itp.cdn.icann.org/en/files/root-
              system/identification-tld-private-use-24-01-2024-en.pdf>.

   [ICANN-Board-Resolution]
              "Reserving .INTERNAL for Private-Use Applications", July
              2024, <https://www.icann.org/en/board-activities-and-
              meetings/materials/approved-resolutions-special-meeting-
              of-the-icann-board-29-07-2024-en#section2.a>.

   [RFC1918]  Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G.
              J., and E. Lear, "Address Allocation for Private
              Internets", BCP 5, RFC 1918, DOI 10.17487/RFC1918,
              February 1996, <https://www.rfc-editor.org/rfc/rfc1918>.

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   [RFC9476]  Kumari, W. and P. Hoffman, "The .alt Special-Use Top-Level
              Domain", RFC 9476, DOI 10.17487/RFC9476, September 2023,
              <https://www.rfc-editor.org/rfc/rfc9476>.

   [SAC113]   "SSAC Advisory on Private-Use TLDs", September 2020,
              <https://itp.cdn.icann.org/en/files/security-and-
              stability-advisory-committee-ssac-reports/sac-113-en.pdf>.

Notes (for removal before publication)

   I-D source is maintained at: https://github.com/kjd/draft-davies-
   internal-tld

Acknowledgments

   TBD

Contributors

   Paul Hoffman
   ICANN
   Email: paul.hoffman@icann.org

Authors' Addresses

   Kim Davies
   Internet Assigned Numbers Authority
   Email: kim.davies@iana.org

   Andrew McConachie
   Internet Corporation for Assigned Names and Numbers
   Email: andrew.mcconachie@icann.org

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