Two DNS Resolver Information Keys for DNSSEC and DNS64
draft-bortzmeyer-add-resinfo-dnssecval-dns64-01
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Stéphane Bortzmeyer , Florian Obser | ||
| Last updated | 2024-11-07 | ||
| Replaces | draft-bortzmeyer-resinfo-dnssecval, draft-fobser-resinfo-dns64 | ||
| RFC stream | (None) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-bortzmeyer-add-resinfo-dnssecval-dns64-01
Internet Engineering Task Force S. Bortzmeyer
Internet-Draft Afnic
Intended status: Informational F. Obser
Expires: 11 May 2025 OpenBSD
7 November 2024
Two DNS Resolver Information Keys for DNSSEC and DNS64
draft-bortzmeyer-add-resinfo-dnssecval-dns64-01
Abstract
This document specifies two DNS Resolver Information Keys (RFC 9606)
for DNSSEC validation capability, "dnssecval" and DNS64 synthesis,
"dns64".
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 11 May 2025.
Copyright Notice
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. The key "dnssecval" . . . . . . . . . . . . . . . . . . . . . 3
3. The key "dns64" . . . . . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
6.1. Normative References . . . . . . . . . . . . . . . . . . 4
6.2. Informative References . . . . . . . . . . . . . . . . . 4
Appendix A. Discussions and alternatives . . . . . . . . . . . . 5
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
RFC 9606 specifies a DNS resource record (RR) type RESINFO to allow
resolvers to publish information about their capabilities and
policies. This information is encoded as {key, value} pairs, with
each information is unambiguously identified with a key. Keys are
maintained in an IANA registry. This specification adds two new
keys.
The first one indicates that the resolver validates with DNSSEC
[RFC4033][RFC4034][RFC4035]. Such key may be used, for example, by a
DNS client to prefer resolvers that enable DNSSEC validation.
The second key is used for DNS64. DNS64 [RFC6147] is performed by a
DNS resolver together with NAT64 [RFC6146] to allow an IPv6-only
client to initiate communications by name to an IPv4-only server.
The new key can be used to inform DNS clients that DNS64 is performed
by the DNS resolver.
Note that, per the rules for the keys defined in Section 6.4 of
[RFC6763] if there is no '=' in a key, then it is a boolean
attribute, simply identified as being present, with no value. The
two keys are therefore simple booleans.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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2. The key "dnssecval"
The name of the key is "dnssecval", for "DNSSEC validating
[resolver]". The presence of this key indicates that the DNS
resolver validates all answers with DNSSEC [RFC4033] [RFC4034]
[RFC4035].
A resolver that announces this capability in a RESINFO record MAY add
DNSSEC-specific EDE (Extended DNS Error Codes, [RFC8914]) to the
value of the "exterr" key, e.g., "Unsupported DNSKEY Algorithm",
"Unsupported DS Digest Type", and "DNSSEC Bogus". Refer to the
"Extended DNS Error Codes" registry for a definitive list of these
EDEs.
3. The key "dns64"
The name of the key is simply "dns64". The presence of this key
indicates that the DNS resolver performs address synthesis. A
resolver which supports [RFC9606] SHOULD add the dns64 key if it
performs DNS64 [RFC6147] address synthesis.
4. IANA Considerations
This document requests IANA to add the key "dnssecval", with the
explanation text "The presence of the key name indicates that DNSSEC
validation is enabled", and a reference to this document to the
registry "DNS Resolver Information Keys" under the "Domain Name
System (DNS) Parameters" registry group.
This document requests IANA to add the key "dns64", with the
explanation text "The presence of the key indicates that DNS64
address synthesis is performed", and a reference to this document to
the registry "DNS Resolver Information Keys" under the "Domain Name
System (DNS) Parameters" registry group.
+===========+==============================+===============+
| Name | Description | Reference |
+===========+==============================+===============+
| dnssecval | The presence of the key name | RFC EDITOR: |
| | indicates that DNSSEC | replace : |
| | validation is enabled. | This_Document |
+-----------+------------------------------+---------------+
| dns64 | The presence of the key | RFC EDITOR: |
| | indicates that DNS64 address | replace : |
| | synthesis is performed | This_Document |
+-----------+------------------------------+---------------+
Table 1
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5. Security Considerations
DNSSEC is a very important tool for the security of the DNS.
Therefore it is important for users to know in advance whether the
resolver they consider supports DNSSEC. It would be better to assume
that every resolver validates (thus rendering this document useless)
but it is not the case today.
Using the RESINFO mechanism solely to inform clients about the
presence of DNS64 without conveying any prefix information avoids the
security problems of [RFC7050].
As with any information published in the DNS, the keys in the RESINFO
may be wrong or outdated. They should be regarded with care. The
security considerations discussed in Section 7 of [RFC9606] apply.
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
<https://www.rfc-editor.org/info/rfc6763>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC9606] Reddy.K, T. and M. Boucadair, "DNS Resolver Information",
RFC 9606, DOI 10.17487/RFC9606, June 2024,
<https://www.rfc-editor.org/info/rfc9606>.
6.2. Informative References
[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "DNS Security Introduction and Requirements",
RFC 4033, DOI 10.17487/RFC4033, March 2005,
<https://www.rfc-editor.org/info/rfc4033>.
[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Resource Records for the DNS Security Extensions",
RFC 4034, DOI 10.17487/RFC4034, March 2005,
<https://www.rfc-editor.org/info/rfc4034>.
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[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Protocol Modifications for the DNS Security
Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,
<https://www.rfc-editor.org/info/rfc4035>.
[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, <https://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,
<https://www.rfc-editor.org/info/rfc6147>.
[RFC7050] Savolainen, T., Korhonen, J., and D. Wing, "Discovery of
the IPv6 Prefix Used for IPv6 Address Synthesis",
RFC 7050, DOI 10.17487/RFC7050, November 2013,
<https://www.rfc-editor.org/info/rfc7050>.
[RFC8914] Kumari, W., Hunt, E., Arends, R., Hardaker, W., and D.
Lawrence, "Extended DNS Errors", RFC 8914,
DOI 10.17487/RFC8914, October 2020,
<https://www.rfc-editor.org/info/rfc8914>.
Appendix A. Discussions and alternatives
To be deleted before publication.
It has been proposed to turn "dnssecval" from a boolean into a key
with value ([RFC9606], section 4) to indicate different ways to do
DNSSEC validation. For instance, the PowerDNS resolver has several
levels of validation, see https://doc.powerdns.com/recursor/
dnssec.html. At the present stage, it is the opinion of the authors
that such detailed information is both difficult to standardize
(different resolvers have different knobs to turn) and difficult o
use since the typical consumer will have difficulty understanding
them.
This draft does not suggest what to do with the information provided,
it is up to the consumer. This is inline with [RFC9606], which goal
is to provide information, not guidance.
Acknowledgements
Original idea by Marco Davids.
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Authors' Addresses
Stéphane Bortzmeyer
Afnic
7 avenue du 8 mai 1945
78280 Guyancourt
France
Email: bortzmeyer+ietf@nic.fr
URI: https://www.afnic.fr/
Florian Obser
OpenBSD
Email: florian+ietf@narrans.de
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