Reserved Top Level DNS Names http://tools.ietf.org/html/rfc2606

Request for Comments: 2606 A. Panitz  BCP: 32 June 1999
Category: Best Current Practice
Reserved Top Level DNS Names
[...]
   To safely satisfy these needs, four domain names are reserved as
listed and described below.

.test
.example
.invalid
.localhost

".test" is recommended for use in testing of current or new DNS
related code.

".example" is recommended for use in documentation or as examples.

".invalid" is intended for use in online construction of domain
names that are sure to be invalid and which it is obvious at a
glance are invalid.

The ".localhost" TLD has traditionally been statically defined in
host DNS implementations as having an A record pointing to the
loop back IP address and is reserved for such use. Any other use
would conflict with widely deployed code which assumes this use.

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. IANA Considerations

IANA has agreed to the four top level domain name reservations
specified in this document and will reserve them for the uses
indicated.

5. Security Considerations

Confusion and conflict can be caused by the use of a current or
future top level domain name in experimentation or testing, as an
example in documentation, to indicate invalid names, or as a synonym
for the loop back address. 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.

References

[RFC 1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, November 1987.

[RFC 1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.

[RFC 1591] Postel, J., "Domain Name System Structure and Delegation",
RFC 1591, March 1994.

















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RFC 2606 Reserved Top Level DNS Names June 1999


Authors' Addresses

Donald E. Eastlake 3rd
IBM
65 Shindegan Hill Road, RR #1
Carmel, NY 10512

Phone: +1 914-276-1668(h)
+1 914-784-7913(w)
FAX: +1 914-784-3833(3)
EMail: dee3@us.ibm.com


Aliza R. Panitz
500 Stamford Dr. No. 310
Newark, DE 19711 USA

Phone: +1 302-738-1554
EMail: buglady@fuschia.net
































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RFC 2606 Reserved Top Level DNS Names June 1999


Full Copyright Statement

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Acknowledgement

Funding for the RFC Editor function is currently provided by the
Internet Society.



















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