INTERNET-DRAFT Example, Test, & Fictitious TLDs
March 1998
Expires September 1998
Example, Test, and Fictitious Top Level DNS Names
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Donald E. Eastlake 3rd
Aliza R. Panitz
Status of This Document
This draft, file name draft-ietf-dnsind-test-tlds-08.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
<namedroppers@internic.net> 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 ds.internic.net (East USA), ftp.isi.edu (West USA),
ftp.nordu.net (North Europe), ftp.nis.garr.it (South Europe),
munnari.oz.au (Pacific Rim), or ftp.is.co.za (Africa).
[Changes in this draft from the last version resulted from discussion
with IANA.]
D. Eastlake, A. Panitz [Page 1]
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INTERNET-DRAFT Example, Test, & Fictitious TLDs
Abstract
To reduce the likelihood of conflict and confusion, a number of top
level domain names are reserved for use in creating names for
fictional purposes, private testing, as examples in documentation,
and the like. In addition, a few second level domain names reserved
for use as examples are documented.
Table of Contents
Status of This Document....................................1
Abstract...................................................2
Table of Contents..........................................2
1. Introduction............................................3
2. TLDs for Fictional, Testing, & Documentation Examples...3
3. Reserved Example Second Level Domain Names..............6
4. Security Considerations.................................6
References.................................................7
Authors Addresses..........................................7
Expiration and File Name...................................7
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INTERNET-DRAFT Example, Test, & Fictitious TLDs
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 Fictional, Testing, & Documentation Examples
There is a need for top level domain (TLD) names that can be used for
creating names which, without fear of conflicts with current or
future actual TLD names in the global DNS, can be used for (1)
realistic fictional names for literary or other purposes, (2) private
testing of existing DNS related code, (3) examples in documentation,
(4) DNS related experimentation, (5) invalid DNS names, or (6) other
similar uses.
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
versions. Or a work of fictional literature might be written with
realistic fake domain names under a fake TLD, perhaps in URLs, which
later caused confusion when that TLD came into actual use. 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 escape 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 to be referencing a TLD permanently reserved
for such purposes.
To safely satisfy these needs, domain names are reserved as described
below. It is best to allocate a variety 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.
The following eight top level domain names are reserved.
D. Eastlake, A. Panitz [Page 3]
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INTERNET-DRAFT Example, Test, & Fictitious TLDs
.xy
.xz
.nil
.tld
.test
.example
.invalid
.localhost
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 special use in forming fictional names,
in testing, as examples in documentation, etc. except for
".localhost" which is reserved for use as the local name of the
loopback IP addresses (IPv4 and IPv6).
".invalid" is intended for use in online construction of domain names
that are sure to be and are self labeled as invalid. By appending
".invalid" to a domain name, you are sure of constructing a name that
is not valid. 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.
".test" is particularly recommended for use in testing of current or
new DNS related code..
".example" is particularly recommended for use in documentation or as
examples.
It is recommended that fictional domain names be constructed using
".xy", ".xz", ".nil", and ".tld".
[At the time of the issuance of this draft as an RFC, IANA will
determine which, if any, of the above names will actually be entered
into the IETF recommended root zone with a single TXT RR for each
that will contain the string
Reserved, see RFC nnnn.
or such other information as IANA determines. This text within
square brackets will be modified to indicate which names are actually
entered in root and what RR or RRs will be stored under them.
Other data will not be stored under these names in the root zone
except that the loopback A and AAAA [RFC 1886] resource records may
be stored under ".localhost". However, to assure proper operation of
D. Eastlake, A. Panitz [Page 4]
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INTERNET-DRAFT Example, Test, & Fictitious TLDs
hosts even when unable to access a root server, ".localhost" should
still be locally staticly configured.
[Note to RFC-Editor: replace nnnn above with the number of the RFC
this draft gets issued as.]]
D. Eastlake, A. Panitz [Page 5]
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INTERNET-DRAFT Example, Test, & Fictitious TLDs
3. Reserved Example Second Level Domain Names
The Internet Assigned Numbers Authority (IANA) also currently has the
following second level domain names reserved which can be used as
examples.
example.com
example.net
example.org
4. Security Considerations
Confusion and conflict can be caused by the use of a current or
future top level domain name as a fictitious name in literature, in
experimentation or testing, 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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INTERNET-DRAFT Example, Test, & Fictitious TLDs
References
RFC 1034 - P. Mockapetris, "Domain names - concepts and facilities",
11/01/1987.
RFC 1035 - P. Mockapetris, "Domain names - implementation and
specification", 11/01/1987.
RFC 1591 - J. Postel, "Domain Name System Structure and Delegation",
03/03/1994.
RFC 1886 - S. Thomson, C. Huitema, "DNS Extensions to support IP
version 6", December 1995.
Authors 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
email: dee@cybercash.com
Aliza R. Panitz
AccessAbility Internet Services, Inc.
12515 Greenbriar Road
Potomac, MD 20854 USA
Telephone: +1 301 983-3547
FAX: +1 301 983-4899
email: buglady@ability.net
Expiration and File Name
This draft expires September 1998.
Its file name is draft-ietf-dnsind-test-tlds-08.txt.
D. Eastlake, A. Panitz [Page 7]
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