Internet DRAFT - draft-ietf-dnsext-rfc1886bis
draft-ietf-dnsext-rfc1886bis
Internet Engineering Task Force S. Thomson, Cisco
INTERNET-DRAFT C. Huitema, Microsoft
May 12, 2003 V. Ksinant, 6WIND
Expires November 12, 2003 M. Souissi, AFNIC
DNS Extensions to support IP version 6
<draft-ietf-dnsext-rfc1886bis-03.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of [RFC2026].
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
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To view the list Internet-Draft Shadow Directories, see
http://www.ietf.org/shadow.html.
This Internet Draft expires November 12, 2003.
Abstract
This document defines the changes that need to be made to the Domain
Name System to support hosts running IP version 6 (IPv6). The
changes include a resource record type to store an IPv6 address,
a domain to support lookups based on an IPv6 address, and updated
definitions of existing query types that return Internet addresses as
part of additional section processing. The extensions are designed
to be compatible with existing applications and, in particular, DNS
implementations themselves.
This Document combines RFC1886 and changes to RFC 1886 made by
RFC 3152, obsoleting both. Changes mainly consist in replacing
the IP6.INT domain by IP6.ARPA as defined in RFC 3152.
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Table of Contents
1. Introduction............................................. 2
2. New resource record definition and domain................ 2
2.1. AAAA record type.................................... 3
2.2. AAAA data format.................................... 3
2.3. AAAA query.......................................... 3
2.4. Textual format of AAAA records...................... 3
2.5. IP6.ARPA domain..................................... 3
3. Modifications to existing query types.................... 4
4. Security Considerations.................................. 4
5. IANA Considerations...................................... 4
APPENDIX A: Changes from RFC-1886............................ 4
Acknowledgments.............................................. 5
References................................................... 5
Authors' Addresses........................................... 6
Full Copyright Statement..................................... 7
1. INTRODUCTION
Current support for the storage of Internet addresses in the Domain
Name System (DNS)[1,2] cannot easily be extended to support IPv6
addresses[3] since applications assume that address queries return
32-bit IPv4 addresses only.
To support the storage of IPv6 addresses in DNS, this document
defines the following extensions:
o A resource record type is defined to map a domain name to an
IPv6 address.
o A domain is defined to support lookups based on address.
o Existing queries that perform additional section processing to
locate IPv4 addresses are redefined to perform additional
section processing on both IPv4 and IPv6 addresses.
The changes are designed to be compatible with existing software. The
existing support for IPv4 addresses is retained. Transition issues
related to the co-existence of both IPv4 and IPv6 addresses in DNS
are discussed in [4].
2. RESOURCE RECORD DEFINITION AND DOMAIN
A record type is defined to store a host's IPv6 address. A host
that has more than one IPv6 address must have more than one such
record.
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2.1 AAAA record type
The AAAA resource record type is a record specific to the Internet
class that stores a single IPv6 address.
The IANA assigned value of the type is 28 (decimal).
2.2 AAAA data format
A 128 bit IPv6 address is encoded in the data portion of an AAAA
resource record in network byte order (high-order byte first).
2.3 AAAA query
An AAAA query for a specified domain name in the Internet class
returns all associated AAAA resource records in the answer section of
a response.
A type AAAA query does not perform additional section processing.
2.4 Textual format of AAAA records
The textual representation of the data portion of the AAAA resource
record used in a master database file is the textual representation
of a IPv6 address as defined in [3].
2.5 IP6.ARPA Domain
A special domain is defined to look up a record given an address. The
intent of this domain is to provide a way of mapping an IPv6 address
to a host name, although it may be used for other purposes as well.
The domain is rooted at IP6.ARPA.
An IPv6 address is represented as a name in the IP6.ARPA domain by a
sequence of nibbles separated by dots with the suffix ".IP6.ARPA".
The sequence of nibbles is encoded in reverse order, i.e. the
low-order nibble is encoded first, followed by the next low-order
nibble and so on. Each nibble is represented by a hexadecimal digit.
For example, the inverse lookup domain name corresponding to the
address
4321:0:1:2:3:4:567:89ab
would be
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.
ARPA.
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3. MODIFICATIONS TO EXISTING QUERY TYPES
All existing query types that perform type A additional section
processing, i.e. name server (NS), location of services (SRV) and
mail exchange (MX) query types, must be redefined to perform both
type A and type AAAA additional section processing. These definitions
mean that a name server must add any relevant IPv4 addresses and any
relevant IPv6 addresses available locally to the additional section
of a response when processing any one of the above queries.
4. SECURITY CONSIDERATIONS
Any information obtained from the DNS must be regarded as unsafe
unless techniques specified in [7] or [8] are used. The definitions
of the AAAA record type and of the IP6.ARPA domain do not change the
model for use of these techniques.
So, this specification is not believed to cause any new security
problems, nor to solve any existing ones.
5. IANA CONSIDERATIONS
There are no IANA assignments to be performed.
APPENDIX A: Changes from RFC 1886
The following changes were made from RFC 1886 "DNS Extensions to
support IP version 6":
- Replaced the "IP6.INT" domain by "IP6.ARPA".
- Mentioned SRV query types in section 3 "MODIFICATIONS TO
EXISTING QUERY TYPES"
- Added security considerations.
- Updated references :
* From RFC 1884 to RFC 3513 (IP Version 6 Addressing
Architecture).
* From "work in progress" to RFC 2893 (Transition Mechanisms for
IPv6 Hosts and Routers).
* Added reference to RFC 1886, RFC 3152, RFC 2535 and RFC 2845.
- Updated document abstract
- Added table of contents
- Added full copyright statement
- Added IANA considerations section
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Acknowledgements
Vladimir Ksinant and Mohsen Souissi would like to thank Sebastien
Barbin (IRISA), Luc Beloeil (France Telecom R&D), Jean-Mickael
Guerin (6WIND), Vincent Levigneron (AFNIC), Alain Ritoux (6WIND),
Frederic Roudaut (IRISA) and G6 group for their help during the RFC
1886 Interop tests sessions.
Many thanks to Alain Durand and Olafur Gudmundsson for their support.
Normative References
[1] Mockapetris, P., "Domain Names - Concepts and Facilities", STD
13, RFC 1034, USC/Information Sciences Institute, November 1987.
[2] Mockapetris, P., "Domain Names - Implementation and Specifica-
tion", STD 13, RFC 1035, USC/Information Sciences Institute,
November 1987.
Informative References
[3] Hinden, R., and S. Deering, "Internet Protocol Version 6 (IPv6)
Addressing Architecture", RFC 3513, Nokia, Cisco, April 2003.
[4] Gilligan, R., and E. Nordmark, "Transition Mechanisms for IPv6
Hosts and Routers", RFC 2893, FreeGate Corp., Sun Microsystems
Inc., August 2000.
This RFC is being updated. The current draft is
"draft-ietf-v6ops-mech-v2-00.txt", Gilligan, R., and
E. Nordmark, February 24, 2003
[5] Thomson, S., and C. Huitema, "DNS Extensions to support IP
version 6", RFC 1886, Bellcore, INRIA, December 1995.
[6] Bush, R., "Delegation of IP6.ARPA", RFC 3152, RGnet, August
2001.
[7] Eastlake, D., "Domain Name System Security Extensions",
RFC 2535, IBM, March 1999
[8] Vixie, P., Gudmundsson, O., Eastlake, D. and B. Wellington,
"Secret Key Transaction Authentication for DNS (TSIG)",
RFC 2845, ISC, NAI Labs, Motorola, Nominum, May 2000.
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Authors' Addresses
Susan Thomson
Cisco Systems
499 Thornall Street, 8th floor
Edison, NJ 08837
Telephone: 732-635-3086
Email: sethomso@cisco.com
Christian Huitema
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052-6399
Email: huitema@microsoft.com
Vladimir Ksinant
6WIND S.A.
Immeuble Central Gare - Bat.C
1, place Charles de Gaulle
78180, Montigny-Le-Bretonneux - France
Phone: +33 1 39 30 92 36
Email: vladimir.ksinant@6wind.com
Mohsen Souissi
AFNIC
Immeuble International
2, rue Stephenson,
78181, Saint-Quentin en Yvelines Cedex - France
Phone: +33 1 39 30 83 40
Email: Mohsen.Souissi@nic.fr
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