Network Working Group C. Bao
Internet-Draft X. Li
Intended status: Informational CERNET Center/Tsinghua
Expires: August 1, 2017 University
January 28, 2017
DNS46 for the IPv4/IPv6 Stateless Translator
draft-xli-behave-dns46-for-stateless-06
Abstract
The stateless translator can support IPv6-initiated communications as
well as IPv4-initiated communications for IPv6 hosts using IPv4-
translatable addresses. DNS support for the IPv6-initiated
communication is defined in the DNS64 specification. This document
defines the DNS46 function for the stateless translator.
Status of this Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on August 1, 2017.
Copyright Notice
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document authors. All rights reserved.
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3
3. DNS46 for the IPv4/IPv6 Stateless Translator . . . . . . . . . 3
3.1. Authoritative DNS server . . . . . . . . . . . . . . . . . 3
3.1.1. Static AAAA record . . . . . . . . . . . . . . . . . . 3
3.1.2. Varying AAAA record . . . . . . . . . . . . . . . . . . 4
3.2. DNS resolver . . . . . . . . . . . . . . . . . . . . . . . 4
3.2.1. DNS resolver for scenario 6 . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5
7. Normative References . . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
DNS mechanism is one of the functions model for the IPv4/IPv6
transition [RFC6144]. DNS64 allows IPv6 hosts to resolve names of
IPv4 hosts whereas DNS46 allows IPv4 hosts to resolve names of IPv6
hosts.
General DNS46 is considered harmful, as NAT-PT was deprecated by IETF
[RFC4966]. However, stateless translators can support IPv6-initiated
communications (scenario 1 and 3) which requires the DNS64 support
[RFC6146] [RFC6145], as well as IPv4-initiated communications
(scenario 2 and 4) which requires the DNS46 support [RFC6145].
DNS64 is used for both stateful and stateless translators and it is
defined in [RFC6147]. DNS46 is only used for the stateless
translators and it is defines in this document.
2. Notational Conventions
The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
document, are to be interpreted as described in [RFC2119].
3. DNS46 for the IPv4/IPv6 Stateless Translator
The DNS46 for stateless IPv4/IPv6 translation is for the following
scenarios:
o Scenario 2: The IPv4 Internet to an IPv6 network.
o Scenario 6: An IPv4 network to an IPv6 network.
3.1. Authoritative DNS server
Since the destination is "an IPv6 network", DNS46 can be deployed as
an authoritative DNS server [RFC1035] in an IPv6 network.
3.1.1. Static AAAA record
This is very similar to the authoritative DNS configuration of dual-
stack hosts. The only difference is that in the dual-stack case, the
A record and AAAA record are independent, while in stateless
translation case, the hosts are typically IPv6 single stack (or for
some reason incapable of using IPv4 on a particular network) using
IPv4-translatable addresses and the A record MUST be derived from the
AAAA record based on the algorithm and the PREFIX information
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[RFC6052].
3.1.2. Varying AAAA record
If an IPv6 host has a varying AAAA record (that is, it could change
due to the IPv6-only host changing its IPv6 address and registering
its new address via, for example, DNS Dynamic Updates [RFC2316]),
then the dynamic DNS46 function is required. However, it is still
the authoritative DNS. When the authoritative DNS receives a dynamic
update containing AAAA record, it MUST synthesize corresponding A
record before signing the zone, which can be derived based on the
algorithm and the PREFIX information [RFC6052].
3.2. DNS resolver
For scenario 2 (the IPv4 Internet to an IPv6 network) the
implementation of DNS46 resolver is almost impossible, since the IPv4
hosts are in the IPv4 Internet.
3.2.1. DNS resolver for scenario 6
However, for scenario 6 (an IPv4 network to IPv6 network) [RFC6144],
it is possible to use DNS resolver in an IPv4 network to synthesize A
records from the AAAA records based on the algorithm and the PREFIX
information [RFC6052].
4. Security Considerations
When DNS46 function is provided by authoritative DNS server, DNS46
can support DNSSEC without problem.
When DNS46 function is provided by authoritative DNS server, the
reverse DNS is also under the same network operator's control which
may provide additional validation function for the IPv4-translatable
IPv6 addresses.
5. IANA Considerations
This memo adds no new IANA considerations.
Note to RFC Editor: This section will have served its purpose if it
correctly tells IANA that no new assignments or registries are
required, or if those assignments or registries are created during
the RFC publication process. From the author's perspective, it may
therefore be removed upon publication as an RFC at the RFC Editor's
discretion.
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6. Acknowledgments
The authors would like to acknowledge the following contributors of
this document: Branimir Rajtar, Dan Wing and Kevin Yin.
7. Normative References
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
November 1987, <http://www.rfc-editor.org/info/rfc1035>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2316] Bellovin, S., "Report of the IAB Security Architecture
Workshop", RFC 2316, DOI 10.17487/RFC2316, April 1998,
<http://www.rfc-editor.org/info/rfc2316>.
[RFC4966] Aoun, C. and E. Davies, "Reasons to Move the Network
Address Translator - Protocol Translator (NAT-PT) to
Historic Status", RFC 4966, DOI 10.17487/RFC4966,
July 2007, <http://www.rfc-editor.org/info/rfc4966>.
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
DOI 10.17487/RFC6052, October 2010,
<http://www.rfc-editor.org/info/rfc6052>.
[RFC6144] Baker, F., Li, X., Bao, C., and K. Yin, "Framework for
IPv4/IPv6 Translation", RFC 6144, DOI 10.17487/RFC6144,
April 2011, <http://www.rfc-editor.org/info/rfc6144>.
[RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", RFC 6145, DOI 10.17487/RFC6145, April 2011,
<http://www.rfc-editor.org/info/rfc6145>.
[RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful
NAT64: Network Address and Protocol Translation from IPv6
Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146,
April 2011, <http://www.rfc-editor.org/info/rfc6146>.
[RFC6147] Bagnulo, M., Sullivan, A., Matthews, P., and I. van
Beijnum, "DNS64: DNS Extensions for Network Address
Translation from IPv6 Clients to IPv4 Servers", RFC 6147,
DOI 10.17487/RFC6147, April 2011,
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<http://www.rfc-editor.org/info/rfc6147>.
Authors' Addresses
Congxiao Bao
CERNET Center/Tsinghua University
Room 225, Main Building, Tsinghua University
Beijing 100084
CN
Phone: +86 10-62785983
Email: congxiao@cernet.edu.cn
Xing Li
CERNET Center/Tsinghua University
Room 225, Main Building, Tsinghua University
Beijing 100084
CN
Phone: +86 10-62785983
Email: xing@cernet.edu.cn
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