Network Working Group T. April
Internet-Draft
Intended status: Standards Track P. Špaček
Expires: 4 September 2025 ISC
R. Weber
Akamai Technologies
D. Lawrence
Salesforce
3 March 2025
Extensible Delegation for DNS using different transport protocols
draft-wesplaap-deleg-transport-00
Abstract
This document extends DELEG record, and SVCB records pointed to by
DELEG record, as defined in [I-D.draft-wesplaap-deleg], with ability
to specify transport protocols and authentication parameters
supported by name servers.
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 4 September 2025.
Copyright Notice
Copyright (c) 2025 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Please review these documents carefully, as they describe your rights
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extracted from this document must include Revised BSD License text as
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
2. New DNS transports . . . . . . . . . . . . . . . . . . . . . 3
2.1. Selecting transport protocols . . . . . . . . . . . . . . 3
2.2. Authenticating transport protocols . . . . . . . . . . . 3
2.2.1. "TLSA" parameter . . . . . . . . . . . . . . . . . . 4
2.2.2. Authentication Failures . . . . . . . . . . . . . . . 4
3. Privacy Considerations . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5.1. New SvcParamKey Values . . . . . . . . . . . . . . . . . 4
6. Informative References . . . . . . . . . . . . . . . . . . . 4
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 6
Appendix B. TODO . . . . . . . . . . . . . . . . . . . . . . . . 6
Appendix C. Change Log . . . . . . . . . . . . . . . . . . . . . 6
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
The new delegation mechanism based on DELEG record type allows to
specify attributes a resolver can use when talking to a delegated
authority. This document introduces parameters specific to different
transport mechanism than the default udp/53 protocol.
Legacy DNS resolvers unaware of DELEG mechanism would continue to use
the NS and DS records, while resolvers that understand DELEG and its
associated parameters can efficiently switch to new transports.
1.1. Terminology
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.
Terminology regarding the Domain Name System comes from [BCP219],
with addition terms defined here:
* legacy transport name servers: An authoritative name server that
only supports unencrypted DNS via UDP/TCP port 53
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2. New DNS transports
There has been a lot of work defining new ways to transport DNS over
new encrypted protocols. While most of this work was focusd on the
client/stub resolver to recursive resolver connection the protocols
will remain the same for an recursive to authoritative connections
when iterating for a name. These are:
* DNS over TLS as defined in [RFC7858]
* DNS over HTTPS as defined in [RFC8484]
* DNS over Dedicated QUIC Connections RFC9250
While the DNS over HTTPs recommends HTTP/2 [RFC9113] as the minimum
version there are no differences when using to over HTTP/3 [RFC9114].
2.1. Selecting transport protocols
The selection of the transport protocol to use to connect to an
authoritative server for a delegation is done by the ALPN parameter
as defined in [RFC9460].
If there is no ALPN parameter the connection MUST be established
using unencrypted DNS over UDP/TCP on port 53.
If there is an ALPN parameter up to 4 protocols in the list MUST be
tried to connect to the authoritative server.
The following ALPN are allowed to be used and may need the additional
parameters as defined in this table: | ALPN |
parameters | |-------|------------| | dot | | | doq | | | h2 |
dohpath | | h3 | dohpath |
2.2. Authenticating transport protocols
As all defined transport protocols here rely on TLS the
authentication for the authentication of them is identical. When no
TLSA parameter is present authentication is MUST be done using the
normal PKI infrastructure of the recursive resolver. The name used
for the authentication is the target name of the DELEG or SVCB
record. When a TLSA paramert is present the authentication MUST be
done using the digests in that record
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2.2.1. "TLSA" parameter
The "TLSA" SvcParamKey is a transport parameter representing a TLSA
RRset [RFC6698] to be used when connecting to TargetName using a TLS-
based transport.
The SvcParamValue is a non-empty value-list. The presentation and
wire format of each value is the same as the presentation and wire
format described for the TLSA record as defined in [RFC6698],
sections 2.1 and 2.2 respectively. To avoid wasting resources in the
parent zone parents MAY reject RRSets containing "tlsa" SvcParams
that use matching type 0 (exact match).
2.2.2. Authentication Failures
When a resolver attempts to access nameserver delegated by a DELEG or
SVCB record, if a connection error occurs, such as a certificate
mismatch or unreachable server, the resolver SHOULD attempt to
connect to the other nameservers delegated to until either exhausting
the list or the resolver's policy indicates that they should treat
the resolution as failed.
3. Privacy Considerations
All of the information handled or transmitted by this protocol is
public information published in the DNS.
4. Security Considerations
TODO: Fill this section out
5. IANA Considerations
5.1. New SvcParamKey Values
This document defines new SvcParamKey values in the "Service Binding
(SVCB) Parameter Registry".
+=============+======+============+=================+
| SvcParamKey | NAME | Meaning | Reference |
+=============+======+============+=================+
| TBD1 | tlsa | TLSA RRset | (This Document) |
+-------------+------+------------+-----------------+
Table 1
6. Informative References
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[BCP219] Best Current Practice 219,
<https://www.rfc-editor.org/info/bcp219>.
At the time of writing, this BCP comprises the following:
Hoffman, P. and K. Fujiwara, "DNS Terminology", BCP 219,
RFC 9499, DOI 10.17487/RFC9499, March 2024,
<https://www.rfc-editor.org/info/rfc9499>.
[I-D.draft-wesplaap-deleg]
April, T., Špaček, P., Weber, R., and Lawrence,
"Extensible Delegation for DNS", Work in Progress,
Internet-Draft, draft-wesplaap-deleg-02, 18 February 2025,
<https://datatracker.ietf.org/doc/html/draft-wesplaap-
deleg-02>.
[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/rfc/rfc2119>.
[RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication
of Named Entities (DANE) Transport Layer Security (TLS)
Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August
2012, <https://www.rfc-editor.org/rfc/rfc6698>.
[RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D.,
and P. Hoffman, "Specification for DNS over Transport
Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May
2016, <https://www.rfc-editor.org/rfc/rfc7858>.
[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/rfc/rfc8174>.
[RFC8484] Hoffman, P. and P. McManus, "DNS Queries over HTTPS
(DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018,
<https://www.rfc-editor.org/rfc/rfc8484>.
[RFC9113] Thomson, M., Ed. and C. Benfield, Ed., "HTTP/2", RFC 9113,
DOI 10.17487/RFC9113, June 2022,
<https://www.rfc-editor.org/rfc/rfc9113>.
[RFC9114] Bishop, M., Ed., "HTTP/3", RFC 9114, DOI 10.17487/RFC9114,
June 2022, <https://www.rfc-editor.org/rfc/rfc9114>.
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[RFC9250] Huitema, C., Dickinson, S., and A. Mankin, "DNS over
Dedicated QUIC Connections", RFC 9250,
DOI 10.17487/RFC9250, May 2022,
<https://www.rfc-editor.org/rfc/rfc9250>.
[RFC9460] Schwartz, B., Bishop, M., and E. Nygren, "Service Binding
and Parameter Specification via the DNS (SVCB and HTTPS
Resource Records)", RFC 9460, DOI 10.17487/RFC9460,
November 2023, <https://www.rfc-editor.org/rfc/rfc9460>.
Appendix A. Acknowledgments
This draft is heavily based on past work (draft-tapril-ns2) done by
Tim April and thus extends the thanks to the people helping on this
which are: John Levine, Erik Nygren, Jon Reed, Ben Kaduk, Mashooq
Muhaimen, Jason Moreau, Jerrod Wiesman, Billy Tiemann, Gordon Marx
and Brian Wellington.
Appendix B. TODO
RFC EDITOR: PLEASE REMOVE THE THIS SECTION PRIOR TO PUBLICATION.
* Write a security considerations section
Appendix C. Change Log
RFC EDITOR: PLEASE REMOVE THE THIS SECTION PRIOR TO PUBLICATION.
~~~ 01234567890123456789012345678901234567890123456789012345678901234
567891
Contributors
Christian Elmerot
Cloudflare
Email: christian@elmerot.se
Edward Lewis
ICANN
Email: edward.lewis@icann.org
Shumon Huque
Salesforce
Email: shuque@gmail.com
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Klaus Darilion
nic.at
Email: klaus.darilion@nic.at
Libor Peltan
CZ.nic
Email: libor.peltan@nic.cz
Vladimír Čunát
CZ.nic
Email: vladimir.cunat@nic.cz
Shane Kerr
NS1
Email: shane@time-travellers.org
David Blacka
Verisign
Email: davidb@verisign.com
George Michaelson
APNIC
Email: ggm@algebras.org
Ben Schwartz
Meta
Email: bemasc@meta.com
Jan Včelák
NS1
Email: jvcelak@ns1.com
Peter van Dijk
PowerDNS
Email: peter.van.dijk@powerdns.com
Philip Homburg
NLnet Labs
Email: philip@nlnetlabs.nl
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Erik Nygren
Akamai Technologies
Email: erik+ietf@nygren.org
Vandan Adhvaryu
Team Internet
Email: vandan@adhvaryu.uk
Manu Bretelle
Meta
Email: chantr4@gmail.com
Authors' Addresses
Tim April
Email: ietf@tapril.net
Petr Špaček
ISC
Email: pspacek@isc.org
Ralf Weber
Akamai Technologies
Email: rweber@akamai.com
David C Lawrence
Salesforce
Email: tale@dd.org
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