Network Working Group F. Ellermann Internet-Draft xyzzy Obsoletes: 2606 (if approved) June 11, 2008 Intended status: BCP Expires: December 13, 2008 Reserved Top Level DNS Names draft-ellermann-idnabis-test-tlds-03 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on December 13, 2008. Abstract To reduce the likelihood of conflict and confusion, a few 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. This memo replaces RFC 2606. Editorial note This note and the document history (Appendix B) should be removed before publication. The draft can be discussed on the IETF Discussion mailing list. Ellermann Expires December 13, 2008 [Page 1] Internet-Draft Reserved Top Level DNS Names June 2008 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. TLDs for Testing, & Documentation Examples . . . . . . . . . . 3 2.1. ".example" . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2. ".invalid" . . . . . . . . . . . . . . . . . . . . . . . . 4 2.3. ".localhost" . . . . . . . . . . . . . . . . . . . . . . . 4 2.4. ".test" . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Reserved Example Second Level Domain Names . . . . . . . . . . 4 4. Internationalization Considerations . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 6. Security Considerations . . . . . . . . . . . . . . . . . . . 5 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 8.1. Normative References . . . . . . . . . . . . . . . . . . . 6 8.2. Informative References . . . . . . . . . . . . . . . . . . 6 Appendix A. Educational Info . . . . . . . . . . . . . . . . . . 7 Appendix B. Document History . . . . . . . . . . . . . . . . . . 8 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 9 Intellectual Property and Copyright Statements . . . . . . . . . . 10 Ellermann Expires December 13, 2008 [Page 2] Internet-Draft Reserved Top Level DNS Names June 2008 1. Introduction The global Internet Domain Name System is documented in [RFC1034], [RFC1035], [RFC1591], [RFC3696], and numerous additional Requests for Comments. 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. IPv4 addresses used for tests and in examples are specified in [I-D.iana-rfc3330bis], IPv6 addresses used in examples are described in [RFC3849]. The key words "MAY", "RECOMMENDED", and "SHOULD" in this memo are to be interpreted as described in [RFC2119]. 2. TLDs for 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 private testing of existing DNS related code, examples in documentation, DNS related experimentation, invalid DNS names, or 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 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 a 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, four domain names are reserved as listed and described below. See also Section 4. 2.1. ".example" ".example" is RECOMMENDED for use in documentation or as examples. Ellermann Expires December 13, 2008 [Page 3] Internet-Draft Reserved Top Level DNS Names June 2008 2.2. ".invalid" ".invalid" is intended for use in online construction of domain names that are sure to be invalid, and for which it is obvious at a glance that they are invalid. Applications MAY treat ".invalid" as what the name says. 2.3. ".localhost" 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. 2.4. ".test" ".test" is RECOMMENDED for use in testing of current or new DNS related code. Applications SHOULD treat ".test" like any other TLD; a special handling could defeat the purpose of a test. 3. Reserved Example Second Level Domain Names The Internet Assigned Numbers Authority (IANA) also reserves the three second level domain names ".example.com", ".example.net", and ".example.org", which can be used in examples as explained in Section 2.1. When TLDs offer further second level domains for examples, the TLD administrators are encouraged to publish the relevant policies in their TLD as an informational RFC. The second level domain names "nic", "whois", and "www" are often reserved or used for administrative purposes of the TLD, e.g., "whois.example" for the fully qualified domain name of a host with a whois server. As with second level domains for examples this can be an issue in the case of a TLD redelegation. Please note that there are no globally reserved LDH (letter, digit, hyphen) DNS labels below the top level, see [RFC4367]. 4. Internationalization Considerations In 2007 IANA created eleven TLDs for tests of Internationalized Domain Names (IDN). The A-labels and corresponding languages are listed below; see [RFC3490] or its [IDNAbis] successor for details about IDN. Applications SHOULD treat these IDN test TLDs as Ellermann Expires December 13, 2008 [Page 4] Internet-Draft Reserved Top Level DNS Names June 2008 explained in Section 2.4. ".xn--0zwm56d" Chinese (simplified) ".xn--11b5bs3a9aj6g" Hindi ".xn--80akhbyknj4f" Russian ".xn--9t4b11yi5a" Korean ".xn--deba0ad" Yiddish ".xn--g6w251d" Chinese (traditional) ".xn--hgbk6aj7f53bba" Persian ".xn--hlcj6aya9esc7a" Tamil ".xn--jxalpdlp" Greek ".xn--kgbechtv" Arabic ".xn--zckzah" Japanese 5. IANA Considerations IANA reserves the TLDs ".example", ".invalid", ".localhost", ".test", and eleven IDN test TLDs as noted above. IANA reserves the second level domains ".example.com", ".example.net", and ".example.org". IANA creates a registry of reserved TLDs; this can be done alongside existing IANA TLD registries at the discretion of IANA. The registry should contain references to the relevant specifications, for the fifteen reserved TLDs specified here references to this memo will do. Additional reserved TLDs require IETF review as defined in [RFC5226] in conjunction with [RFC2860]. 6. 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 minimizes such confusion and conflict. [RFC4367] discusses various false assumptions based on domain labels, however this doesn't affect the reserved TLDs in this memo. Readers need to be aware that the IANA registry of reserved TLDs in Ellermann Expires December 13, 2008 [Page 5] Internet-Draft Reserved Top Level DNS Names June 2008 Section 5 won't list all reserved TLDs for specific applications and protocols. The registry can only list reserved TLDs if somebody bothered to propose it, typically in an Internet-Draft, and the proposal was accepted in an IETF review. 7. Acknowledgments This memo contains major parts of [RFC2606] written by Donald E. Eastlake and Aliza R. Panitz. Thanks to David Cridland, John C. Klensin, Sumit Pandya, Tina Dam, and Tony Hansen for their feedback, contributions, or encouragement. 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. 8.2. Informative References [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", STD 13, RFC 1034, November 1987. [RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987. [RFC1591] Postel, J., "Domain Name System Structure and Delegation", RFC 1591, March 1994. [RFC2606] Eastlake, D. and A. Panitz, "Reserved Top Level DNS Names", BCP 32, RFC 2606, June 1999. [RFC2860] Carpenter, B., Baker, F., and M. Roberts, "Memorandum of Understanding Concerning the Technical Work of the Internet Assigned Numbers Authority", RFC 2860, June 2000. [RFC2965] Kristol, D. and L. Montulli, "HTTP State Management Mechanism", RFC 2965, October 2000. [RFC3490] Faltstrom, P., Hoffman, P., and A. Costello, Ellermann Expires December 13, 2008 [Page 6] Internet-Draft Reserved Top Level DNS Names June 2008 "Internationalizing Domain Names in Applications (IDNA)", RFC 3490, March 2003. [RFC3696] Klensin, J., "Application Techniques for Checking and Transformation of Names", RFC 3696, February 2004. [RFC3849] Huston, G., Lord, A., and P. Smith, "IPv6 Address Prefix Reserved for Documentation", RFC 3849, July 2004. [RFC3927] Cheshire, S., Aboba, B., and E. Guttman, "Dynamic Configuration of IPv4 Link-Local Addresses", RFC 3927, May 2005. [RFC4367] Rosenberg, J. and IAB, "What's in a Name: False Assumptions about DNS Names", RFC 4367, February 2006. [I-D.iana-rfc3330bis] Cotton, M., "Special Use IPv4 Addresses", draft-iana-rfc3330bis-03 (work in progress), June 2008. [IDNAbis] IETF, "Internationalized Domain Names in Applications (Revised)", April 2008, . Appendix A. Educational Info This informative appendix tries to answer three frequently answered questions: 1. As of 2008 IANA is the registrant of ".example.edu"; TLD ".edu" has no contract with ICANN; its administration is based on a five years contract with the US DoC renewed in 2006; see . Under amendment 6 of their current policy generic names cannot be registered. This is not exactly the same situation as for say ".example.org", where IANA is the registrant *and* registrar. 2. As of 2008 IANA is the registrant of ".example.info"; TLD ".info" was created by ICANN in 2001. The ".info" registry agreement lists reserved DNS labels including "example"; see appendix 6 (2006) and appendix K (2001). This is not exactly the same situation as for say ".example.org", where IANA is the registrant *and* registrar. 3. Ignoring [RFC2965] the TLD ".local" issue was discussed in a bunch of Internet-Drafts related to AS112, zeroconf, and Ellermann Expires December 13, 2008 [Page 7] Internet-Draft Reserved Top Level DNS Names June 2008 [RFC3927]. Presumably TLD ".local" should be registered as reserved for technical reasons, but deserves its own document with the fine print. Appendix B. Document History Changes in version 03: o Swapped IANA and security considerations based on feedback, since version 01 the order anyway did not more follow . o David Cridland proposed another [RFC4367] caveat, there are no globally reserved LDH labels below the top level. LDH excludes special cases such as the empty label reserved for the root, and leaf labels starting with an underscore. o The informative Appendix A hopefully answers frequently asked questions about ".example.edu", ".example.info", and ".local". o So far nobody insisted on listing the corresponding U-labels for the eleven IDN test TLDs. TBD, it is an editorial layout issue, and somebody offering to check the BiDi U-labels would be great. Changes in version 02: o Added the related [RFC3849] and [I-D.iana-rfc3330bis] references. Added an [RFC4367] reference to the security considerations, as this explains one of many issues with any "well-known" label below the top level. o IDN test SLDs not yet added, it is not clear if they are also reserved TLDs. Any "globally reserved labels" at other levels including the second level would be utter dubious. o Improved the IANA Considerations Section 5 based on feedback. The registry of reserved TLDs needs references to the relevant specifications. o Added a caveat that the IANA registry of reserved TLDs cannot list all obscure ideas of specific applications and protocols; somebody has to trigger an IETF review for new registrations. Changes in version 01: Ellermann Expires December 13, 2008 [Page 8] Internet-Draft Reserved Top Level DNS Names June 2008 o Various editorial issues found by Tony Hansen fixed. o Added [IDNAbis] reference. The author believes that the IETF is not entitled to decree that ".example.edu" belongs to the set of three example-SLDs reserved by IANA. Changes in version 00: o John Klensin suggested clarifying the guidelines for examples in [RFC2606], referenced by . Documenting the eleven new IDN test TLDs was anyway desirable. Author's Address Frank Ellermann xyzzy Hamburg, Germany Email: hmdmhdfmhdjmzdtjmzdtzktdkztdjz@gmail.com URI: http://purl.net/xyzzy/ Ellermann Expires December 13, 2008 [Page 9] Internet-Draft Reserved Top Level DNS Names June 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment This document was produced using xml2rfc v1.33 (of http://xml.resource.org/) from a source in RFC-2629 XML format. Ellermann Expires December 13, 2008 [Page 10]