7Network Working Group S. Thomson
8Request for Comments: 3596 Cisco
9Obsoletes: 3152, 1886 C. Huitema
10Category: Standards Track Microsoft
18 DNS Extensions to Support IP Version 6
22 This document specifies an Internet standards track protocol for the
23 Internet community, and requests discussion and suggestions for
24 improvements. Please refer to the current edition of the "Internet
25 Official Protocol Standards" (STD 1) for the standardization state
26 and status of this protocol. Distribution of this memo is unlimited.
30 Copyright (C) The Internet Society (2003). All Rights Reserved.
34 This document defines the changes that need to be made to the Domain
35 Name System (DNS) to support hosts running IP version 6 (IPv6). The
36 changes include a resource record type to store an IPv6 address, a
37 domain to support lookups based on an IPv6 address, and updated
38 definitions of existing query types that return Internet addresses as
39 part of additional section processing. The extensions are designed
40 to be compatible with existing applications and, in particular, DNS
41 implementations themselves.
45 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
46 2. New resource record definition and domain. . . . . . . . . . . 2
47 2.1. AAAA record type . . . . . . . . . . . . . . . . . . . . 3
48 2.2. AAAA data format . . . . . . . . . . . . . . . . . . . . 3
49 2.3. AAAA query . . . . . . . . . . . . . . . . . . . . . . . 3
50 2.4. Textual format of AAAA records . . . . . . . . . . . . . 3
51 2.5. IP6.ARPA domain. . . . . . . . . . . . . . . . . . . . . 3
52 3. Modifications to existing query types. . . . . . . . . . . . . 4
53 4. Security Considerations. . . . . . . . . . . . . . . . . . . . 4
54 5. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 4
58Thomson, et al. Standards Track [Page 1]
60RFC 3596 DNS Extensions to Support IPv6 October 2003
63 6. Intellectual Property Statement. . . . . . . . . . . . . . . . 4
64 Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . 5
65 Appendix A: Changes from RFC 1886. . . . . . . . . . . . . . . . . 6
66 Normative References . . . . . . . . . . . . . . . . . . . . . . . 6
67 Informative References . . . . . . . . . . . . . . . . . . . . . . 6
68 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
69 Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 8
73 Current support for the storage of Internet addresses in the Domain
74 Name System (DNS) [1,2] cannot easily be extended to support IPv6
75 addresses [3] since applications assume that address queries return
76 32-bit IPv4 addresses only.
78 To support the storage of IPv6 addresses in the DNS, this document
79 defines the following extensions:
81 o A resource record type is defined to map a domain name to an
84 o A domain is defined to support lookups based on address.
86 o Existing queries that perform additional section processing to
87 locate IPv4 addresses are redefined to perform additional
88 section processing on both IPv4 and IPv6 addresses.
90 The changes are designed to be compatible with existing software.
91 The existing support for IPv4 addresses is retained. Transition
92 issues related to the co-existence of both IPv4 and IPv6 addresses in
93 the DNS are discussed in [4].
95 The IP protocol version used for querying resource records is
96 independent of the protocol version of the resource records; e.g.,
97 IPv4 transport can be used to query IPv6 records and vice versa.
99 This document combines RFC 1886 [5] and changes to RFC 1886 made by
100 RFC 3152 [6], obsoleting both. Changes mainly consist in replacing
101 the IP6.INT domain by IP6.ARPA as defined in RFC 3152.
1032. New resource record definition and domain
105 A record type is defined to store a host's IPv6 address. A host that
106 has more than one IPv6 address must have more than one such record.
114Thomson, et al. Standards Track [Page 2]
116RFC 3596 DNS Extensions to Support IPv6 October 2003
121 The AAAA resource record type is a record specific to the Internet
122 class that stores a single IPv6 address.
124 The IANA assigned value of the type is 28 (decimal).
128 A 128 bit IPv6 address is encoded in the data portion of an AAAA
129 resource record in network byte order (high-order byte first).
133 An AAAA query for a specified domain name in the Internet class
134 returns all associated AAAA resource records in the answer section of
137 A type AAAA query does not trigger additional section processing.
1392.4 Textual format of AAAA records
141 The textual representation of the data portion of the AAAA resource
142 record used in a master database file is the textual representation
143 of an IPv6 address as defined in [3].
147 A special domain is defined to look up a record given an IPv6
148 address. The intent of this domain is to provide a way of mapping an
149 IPv6 address to a host name, although it may be used for other
150 purposes as well. The domain is rooted at IP6.ARPA.
152 An IPv6 address is represented as a name in the IP6.ARPA domain by a
153 sequence of nibbles separated by dots with the suffix ".IP6.ARPA".
154 The sequence of nibbles is encoded in reverse order, i.e., the
155 low-order nibble is encoded first, followed by the next low-order
156 nibble and so on. Each nibble is represented by a hexadecimal digit.
157 For example, the reverse lookup domain name corresponding to the
160 4321:0:1:2:3:4:567:89ab
164 b.a.9.8.7.6.5.0.4.0.0.0.3.0.0.0.2.0.0.0.1.0.0.0.0.0.0.0.1.2.3.4.IP6.
170Thomson, et al. Standards Track [Page 3]
172RFC 3596 DNS Extensions to Support IPv6 October 2003
1753. Modifications to existing query types
177 All existing query types that perform type A additional section
178 processing, i.e., name server (NS), location of services (SRV) and
179 mail exchange (MX) query types, must be redefined to perform both
180 type A and type AAAA additional section processing. These
181 definitions mean that a name server must add any relevant IPv4
182 addresses and any relevant IPv6 addresses available locally to the
183 additional section of a response when processing any one of the above
1864. Security Considerations
188 Any information obtained from the DNS must be regarded as unsafe
189 unless techniques specified in [7] or [8] are used. The definitions
190 of the AAAA record type and of the IP6.ARPA domain do not change the
191 model for use of these techniques.
193 So, this specification is not believed to cause any new security
194 problems, nor to solve any existing ones.
1965. IANA Considerations
198 There are no IANA assignments to be performed.
2006. Intellectual Property Statement
202 The IETF takes no position regarding the validity or scope of any
203 intellectual property or other rights that might be claimed to
204 pertain to the implementation or use of the technology described in
205 this document or the extent to which any license under such rights
206 might or might not be available; neither does it represent that it
207 has made any effort to identify any such rights. Information on the
208 IETF's procedures with respect to rights in standards-track and
209 standards-related documentation can be found in BCP-11. Copies of
210 claims of rights made available for publication and any assurances of
211 licenses to be made available, or the result of an attempt made to
212 obtain a general license or permission for the use of such
213 proprietary rights by implementors or users of this specification can
214 be obtained from the IETF Secretariat.
216 The IETF invites any interested party to bring to its attention any
217 copyrights, patents or patent applications, or other proprietary
218 rights which may cover technology that may be required to practice
219 this standard. Please address the information to the IETF Executive
226Thomson, et al. Standards Track [Page 4]
228RFC 3596 DNS Extensions to Support IPv6 October 2003
233 Vladimir Ksinant and Mohsen Souissi would like to thank Sebastien
234 Barbin (IRISA), Luc Beloeil (France Telecom R&D), Jean-Mickael Guerin
235 (6WIND), Vincent Levigneron (AFNIC), Alain Ritoux (6WIND), Frederic
236 Roudaut (IRISA) and G6 group for their help during the RFC 1886
237 Interop tests sessions.
239 Many thanks to Alain Durand and Olafur Gudmundsson for their support.
282Thomson, et al. Standards Track [Page 5]
284RFC 3596 DNS Extensions to Support IPv6 October 2003
287Appendix A: Changes from RFC 1886
289 The following changes were made from RFC 1886 "DNS Extensions to
290 support IP version 6":
292 - Replaced the "IP6.INT" domain by "IP6.ARPA".
293 - Mentioned SRV query types in section 3 "MODIFICATIONS TO
294 EXISTING QUERY TYPES"
295 - Added security considerations.
296 - Updated references :
297 * From RFC 1884 to RFC 3513 (IP Version 6 Addressing
299 * From "work in progress" to RFC 2893 (Transition Mechanisms for
300 IPv6 Hosts and Routers).
301 * Added reference to RFC 1886, RFC 3152, RFC 2535 and RFC 2845.
302 - Updated document abstract
303 - Added table of contents
304 - Added full copyright statement
305 - Added IANA considerations section
306 - Added Intellectual Property Statement
310 [1] Mockapetris, P., "Domain Names - Concepts and Facilities", STD
311 13, RFC 1034, November 1987.
313 [2] Mockapetris, P., "Domain Names - Implementation and
314 Specification", STD 13, RFC 1035, November 1987.
316 [3] Hinden, R. and S. Deering, "Internet Protocol Version 6 (IPv6)
317 Addressing Architecture", RFC 3513, April 2003.
319Informative References
321 [4] Gilligan, R. and E. Nordmark, "Transition Mechanisms for IPv6
322 Hosts and Routers", RFC 2893, August 2000.
324 [5] Thomson, S. and C. Huitema, "DNS Extensions to support IP
325 version 6", RFC 1886, December 1995.
327 [6] Bush, R., "Delegation of IP6.ARPA", BCP 49, RFC 3152, August
330 [7] Eastlake, D., "Domain Name System Security Extensions", RFC
338Thomson, et al. Standards Track [Page 6]
340RFC 3596 DNS Extensions to Support IPv6 October 2003
343 [8] Vixie, P., Gudmundsson, O., Eastlake, D. and B. Wellington,
344 "Secret Key Transaction Authentication for DNS (TSIG)", RFC
351 499 Thornall Street, 8th floor
354 Phone: +1 732-635-3086
355 EMail: sethomso@cisco.com
359 Microsoft Corporation
361 Redmond, WA 98052-6399
363 EMail: huitema@microsoft.com
368 Immeuble Central Gare - Bat.C
369 1, place Charles de Gaulle
370 78180, Montigny-Le-Bretonneux - France
372 Phone: +33 1 39 30 92 36
373 EMail: vladimir.ksinant@6wind.com
378 Immeuble International
380 78181, Saint-Quentin en Yvelines Cedex - France
382 Phone: +33 1 39 30 83 40
383 EMail: Mohsen.Souissi@nic.fr
394Thomson, et al. Standards Track [Page 7]
396RFC 3596 DNS Extensions to Support IPv6 October 2003
399Full Copyright Statement
401 Copyright (C) The Internet Society (2003). All Rights Reserved.
403 This document and translations of it may be copied and furnished to
404 others, and derivative works that comment on or otherwise explain it
405 or assist in its implementation may be prepared, copied, published
406 and distributed, in whole or in part, without restriction of any
407 kind, provided that the above copyright notice and this paragraph are
408 included on all such copies and derivative works. However, this
409 document itself may not be modified in any way, such as by removing
410 the copyright notice or references to the Internet Society or other
411 Internet organizations, except as needed for the purpose of
412 developing Internet standards in which case the procedures for
413 copyrights defined in the Internet Standards process must be
414 followed, or as required to translate it into languages other than
417 The limited permissions granted above are perpetual and will not be
418 revoked by the Internet Society or its successors or assignees.
420 This document and the information contained herein is provided on an
421 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
422 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
423 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
424 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
425 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
429 Funding for the RFC Editor function is currently provided by the
450Thomson, et al. Standards Track [Page 8]