INTERNET-DRAFT                                     Test and Example TLDs
                                                            January 1998
                                                       Expires July 1998

                  Test and Example Top Level DNS Names
                  ---- --- ------- --- ----- --- -----

                         Donald E. Eastlake 3rd
                            Aliza R. Panitz

                        Status of This Document

       This draft, file name draft-ietf-dnsind-test-tlds-07.txt, is
   intended to be become a Best Current Practice RFC.  Distribution of
   this document is unlimited. Comments should be sent to the DNS
   mailing list <> or to the authors.

   This document is an Internet-Draft.  Internet-Drafts are working
   documents of the Internet Engineering Task Force (IETF), its areas,
   and its working groups.  Note that other groups may also distribute
   working documents as Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six
   months.  Internet-Drafts may be updated, replaced, or obsoleted by
   other documents at any time.  It is not appropriate to use Internet-
   Drafts as reference material or to cite them other than as a
   ``working draft'' or ``work in progress.''

   To learn the current status of any Internet-Draft, please check the
   1id-abstracts.txt listing contained in the Internet-Drafts Shadow
   Directories on (East USA), (West USA), (North Europe), (South Europe), (Pacific Rim), or (Africa).


   To reduce the likelihood of conflict and confusion, a number of top
   level domain names are reserved for use in private testing, as
   examples in documentation, and the like. In addition, a few second
   level domain names reserved for use as examples are documented.

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Table of Contents

      Status of This Document....................................1

      Table of Contents..........................................2

      1. Introduction............................................3
      2. TLDs for Testing and Documentation Examples.............3

      3. Reserved Example Second Level Domain Names..............6
      4. Security Considerations.................................6

      Author's Addresses.........................................7
      Expiration and File Name...................................7

D. Eastlake, A. Panitz                                          [Page 2]

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1. Introduction

   The global Internet Domain Name System is documented in [RFC 1034,
   1035, 1591] and numerous additional Requests for Comment.  It defines
   a tree of names starting with root, ".", immediately below which are
   top level domain names such as ".com" and ".us". Below top level
   domain names there are normally additional levels of names.

2. TLDs for Testing and Documentation Examples

   There is a need for top level domain (TLD) names that can safely be
   used in private testing, as examples in documentation, and for
   experimentation, without fear of conflicts with actual top level
   domain names in the global DNS, or which should be reserved to avoid

   For example, without guidance, a site might set up some local
   additional unused top level domains for testing of its local DNS code
   and configuration.  Later, these TLDs might come into actual use on
   the global Internet.  As a result, local attempts to reference the
   real data in these zones could be thwarted by the local test

   Or test or example code might be written that accesses a TLD that is
   in use with the thought that the test code would only be run in
   restricted testbed net or the example never actually run.  Later, the
   test code could esacpe from the testbed or the example be actually
   coded and run on the Internet.  Depending on the nature of the test
   or example, it might be best for it, after its esacpe, to be
   referencing a mostly empty TLD reserved for such purposes.

   To satisfy these needs, domain names are reserved as described below.
   It is thought best to allocate a reasonably large number of names of
   different lengths now to reduce the probability of a need for further
   top level domain name creation and assignment for this purpose in the
   foreseeable future.  On the other hand, there is no reason to horde
   an excessive number of names.  There was a working group consensus
   that the answer to balancing these requirmenets is fourty two names

   The following twelve top level domain names are reserved.

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        Note: two letter top level domain names are reserved for ISO
        3166 / Universal Postal Union two letter country codes.
        However, ISO 3166 reserves all two letter codes beginning with
        "x" for local use and states that they will never be assigned to
        a country.

   These names are available for use in testing or as examples in
   documentation except for ".invalid", ".link", and ".localhost".

   ".invalid" is intended for use in online construction of domain names
   that are sure to be invalid.  By appending ".invalid" to a domain
   name, you are sure of constructing a name that is not valid.  ".link"
   is reserved to avoid confusion with the "link.local" domain provided
   in [draft-ietf-dnsind-local-names-*] and should not be used.  The
   ".localhost" TLD has traditionally been staticly defined in host DNS
   implementations as having an A record pointing to the loop back IP
   address and is reserved for such use.

   The TLDs ".xy", ".nil", and ".test" are particularly recommended for
   use in testing. If a larger number of test names is needed, the
   numeric suffix names listed below should be used.

   The TLDs ".xz", ".tld", ".site", ".bogus", and ".example" are
   particularly recommended for use in documentation or as examples.  If
   a larger number of names is needed in documentation or as examples,
   the numeric suffix names listed below should be used.

   The above twelve names will be added to the root with a single type
   TXT RR under each. The RDATA for these TXT RRs will contain the
   single string

        Reserved, see RFC nnnn.

   [Note to RFC-Editor: replace nnnn above with the number of the RFC
   this draft gets issued as and delete this note]

   Other data will not be stored under these names in the root zone

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   except that the loopback A and AAAA [RFC 1886] resource records may
   be stored under .localhost.  However, to assure proper operation of
   hosts even when unable to access a root server, .localhost must still
   be locally staticly configured.

   In addition, the thirty domain names formed by appending the digits 0
   through 9 to "tld", "test", and "example", as listed below, are also
   reserved for test and documentation use; however, since there are
   currently no TLDs with digits in them and the presence of these names
   without the digit suffix should provide notice, it is not intended
   that these thirty additional TLDs be entered into the root zone at
   this time.

              .tld0        .test0        .example0
              .tld1        .test1        .exmaple1
              .tld2        .test2        .example2
              .tld3        .test2        .example2
              .tld4        .test4        .example4
              .tld5        .test5        .exmaple5
              .tld6        .test6        .example6
              .tld7        .test7        .example7
              .tld8        .test8        .example8
              .tld9        .test9        .example9

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3. Reserved Example Second Level Domain Names

   The Internet Assigned Numbers Authority (IANA) has also reserved the
   following second level domain names which can be used as examples.

4. Security Considerations

   Confusion and conflict can be caused by the use of a current or
   potential future top level domain name in testing, experimentation,
   as an example in documentation, or the like.  Test and experimental
   software can escape and end up being run against the global
   operational DNS.  Even examples used "only" in documentation can end
   up being coded and released or cause conflicts due to later real use
   and the possible acquisition of intellectual property rights in such
   "example" names.

   The reservation of several top level domain names for these purposes
   will minimize such confusion and conflict.

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   GUIDE - D. Adams, "The Hitchhiker's Guide to the Galaxy", 1989.

   RFC 1034 - P. Mockapetris, "Domain names - concepts and facilities",

   RFC 1035 - P. Mockapetris, "Domain names - implementation and
   specification", 11/01/1987.

   RFC 1591 - J. Postel, "Domain Name System Structure and Delegation",

   RFC 1886 - S. Thomson, C. Huitema, "DNS Extensions to support IP
   version 6", December 1995.

   draft-ietf-dnsind-local-names-* - D. Eastlake, "Local DNS Names".

Author's Addresses

   Donald E. Eastlake 3rd
   CyberCash, Inc.
   318 Acton Street
   Carlisle, MA 01741 USA

   Telephone:   +1 978 287 4877
                +1 703 620-4200 (main office, Reston, VA)
   FAX:         +1 978 371 7148

   Aliza R. Panitz
   AccessAbility Internet Services, Inc.
   12515 Greenbriar Road
   Potomac, MD 20854 USA

   Telephone: +1 301 983-3547
   FAX:       +1 301 983-4899

Expiration and File Name

   This draft expires July 1998.

   Its file name is draft-ietf-dnsind-test-tlds-07.txt.

D. Eastlake, A. Panitz                                          [Page 7]