Top-level Domains for Private Internets

Document Type Active Internet-Draft (dnsop WG)
Authors Roy Arends  , Joe Abley 
Last updated 2020-10-08
Replaces draft-dnsop-private-use-tld, draft-arends-private-use-tld
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Independent Submission                                         R. Arends
Internet-Draft                                                     ICANN
Intended status: Best Current Practice                          J. Abley
Expires: April 11, 2021                         Public Interest Registry
                                                        October 08, 2020

                Top-level Domains for Private Internets


   There are no defined private-use namespaces in the Domain Name System
   (DNS).  For a domain name to be considered private-use, it needs to
   be future-proof in that its top-level domain will never be delegated
   from the root zone.  The lack of a private-use namespace has led to
   locally configured namespaces with a top-level domain that is not
   future proof.

   The DNS needs an equivalent of the facilities provided by BCP 5 (RFC
   1918) for private internets, i.e. a range of short, semantic-free
   top-level domains that can be used in private internets without the
   risk of being globally delegated from the root zone.

   The ISO 3166 standard is used for the definition of eligible
   designations for country-code top-level Domains.  This standard is
   maintained by the ISO 3166 Maintenance Agency.  The ISO 3166 standard
   includes a set of user-assigned code elements that can be used by
   those who need to add further names to their local applications.

   Because of the rules set out by ISO in their standard, it is
   extremely unlikely that these user-assigned code elements would ever
   conflict with delegations in the root zone under current practices.
   This document explicitly reserves these code elements to be safely
   used as top-level domains for private DNS resolution.

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
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   This Internet-Draft will expire on April 11, 2021.

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Table of Contents

   1.  Introduction
   2.  The ISO 3166-1 alpha-2 and Two-Letter Top-Level Domains
   3.  ISO 3166-1 alpha-2 User-assigned Code Elements
   4.  Examples of Current Uses of the User-assigned Code Elements.
   5.  Private-use top-level Domains
   6.  IANA Considerations
   7.  Security Considerations
   8.  Acknowledgements
   9.  Informative References
   Authors' Addresses

1.  Introduction

   In private networks where a hostname has no utility in the global
   namespace, it is convenient to have a private-use namespace.  Such
   deployments could theoretically use sub-domains of a domain
   registered for the specific hosting entity, though not all such
   configurations have such a domain available.  When the hostname is
   solely used in a private network, it is not necessary that it
   resolves globally.

   Another situation is where applications use identifiers that are
   similar in appearance to domain names, and may be interpreted by
   software as domain names, but are not intended to use the global DNS
   resolution service.  Using a private-use namespace helps guard
   against conflicts with the global DNS resolution system.

   Note that a private-use namespace is not a subset of a registered
   special use namespace [IANA-Special].  There is no facility to
   register a specific label using the process defined in [RFC6761].
   The process in RFC 6761 requires that a label has some kind of
   special handling in order to be considered special.  A private-use
   namespace can be considered special on a policy level, but not on a
   technical or protocol level.

   Many protocols outside the DNS have a defined set of elements for
   private use, or an identifier that indicates private use, such as
   "X-headers" MIME types [RFC2045], addresses for private internets
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