User Assigned ISO 3166-1 Alpha-2 Codes and the DNS Root Zone
draft-arends-private-use-tld-00

Document Type Active Internet-Draft (individual)
Last updated 2019-11-04
Stream (None)
Intended RFC status (None)
Formats plain text pdf htmlized bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
On Agenda dnsop at IETF-106
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
Independent Submission                                               E. Lewis
Internet-Draft                                                      R. Arends
                                                                        ICANN
Expires: May 3, 2020                                   Date: November 3, 2019

                    User Assigned ISO 3166-1 Alpha-2 Codes
                             and the DNS Root Zone

                         draft-arends-private-use-tld-00

Abstract

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 contains a set of User-Assigned 
code elements. This document describes that these values can be 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
  Task Force (IETF).  Note that other groups may also distribute
  working documents as Internet-Drafts.  The list of current Internet-
  Drafts is at http://datatracker.ietf.org/drafts/current/.

  Internet-Drafts are draft documents valid for a maximum of six months
  and may be updated, replaced, or obsoleted by other documents at any
  time.  It is inappropriate to use Internet-Drafts as reference
  material or to cite them other than as "work in progress."

  This Internet-Draft will expire on May 3, 2020.

Copyright Notice

  Copyright (c) 2019 IETF Trust and the persons identified as the
  document authors.  All rights reserved.

  This document is subject to BCP 78 and the IETF Trust's Legal
  Provisions Relating to IETF Documents
  (http://trustee.ietf.org/license-info) in effect on the date of
  publication of this document.  Please review these documents
  carefully, as they describe your rights and restrictions with respect
  to this document.  Code Components extracted from this document must
  include Simplified BSD License text as described in Section 4.e of
  the Trust Legal Provisions and are provided without warranty as
  described in the Simplified BSD License.

Table of Contents

  1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   1
  2.  Private-Use Top-Level Domain  . . . . . . . . . . . . . . . .   1
  3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   1
  4.  Security Considerations . . . . . . . . . . . . . . . . . . .   1
  5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   1
  6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   1
  7.  Authors' Addresses  . . . . . . . . . . . . . . . . . . . . .   1

1.  Introduction

The practice governing the delegation of ASCII two-letter domain names in
the DNS [STD 13] root zone is to employ the ISO 3166-1 standard [ISO3166-1].
The ISO 3166-1 standard provides for multiple types of codings, with the
ASCII two-letter codes (known as "alpha 2" codes) being used in the DNS to
potentially represent countries and territories as country-code top-level
domains (ccTLDs) [RFC1591]. The interrelationship is documented in "ICANN
and the ISO, A Common Interest in ISO Standard 3166" [ICANN ISO].

In addition to these assigned codes, there are values designated as "User
Assigned". Quoting ISO 3166-1:2013 clause 8.1.3 "User-assigned code elements"
:

   "If users need code elements to represent country names not included
    in this part of ISO 3166, the series of letters AA, QM to QZ, XA to
    XZ, and ZZ, and the series AAA to AAZ, QMA to QZZ, XAA to XZZ, and
    ZZA to ZZZ respectively and the series of numbers 900 to 999 are
    available. 

    NOTE Users are advised that the above series of codes are not
    universals, those code elements are not compatible between different
    entities."

For the purposes of this document, ISO 3166-1 "alpha-2 user-assigned codes"
are defined to be AA, QM to QZ, XA to XZ, and ZZ.  The ranges ("to") are
alphabetic and contain only characters in the US-ASCII definition [RFC20].
The codes are case insensitive.

The quoted text explicitly states "code elements to represent country names"
with the emphasis on the term "country names". Using code elements to 
represent something different than "country names" might at first appear to 
go against the intended use of the standard. However, many organisations, 
including the ISO, have used the user-assigned range to represent entities 
other than country names. The following list is not meant to be exhaustive, 
but to illustrate the different uses of the user-assigned range:

    ISO 3901 uses “ZZ” for direct registrants independent of any country. 
    ISO 4217 uses the “XA..XZ” range for transactions and precious metals. 
    ISO 6166 uses "XS" for securities cleared through Euroclear/Clearstream.

    ICAO uses “ZZ” for UN travel documents. 
    RFC5646 contains a section and examples dedicated to Private Use Sub-tags
Show full document text