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 This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." 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 Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components April, et al. Expires 4 September 2025 [Page 1] Internet-Draft DELEG March 2025 extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are 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 April, et al. Expires 4 September 2025 [Page 2] Internet-Draft DELEG March 2025 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 April, et al. Expires 4 September 2025 [Page 3] Internet-Draft DELEG March 2025 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 April, et al. Expires 4 September 2025 [Page 4] Internet-Draft DELEG March 2025 [BCP219] Best Current Practice 219, . 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, . [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, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [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, . [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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8484] Hoffman, P. and P. McManus, "DNS Queries over HTTPS (DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018, . [RFC9113] Thomson, M., Ed. and C. Benfield, Ed., "HTTP/2", RFC 9113, DOI 10.17487/RFC9113, June 2022, . [RFC9114] Bishop, M., Ed., "HTTP/3", RFC 9114, DOI 10.17487/RFC9114, June 2022, . April, et al. Expires 4 September 2025 [Page 5] Internet-Draft DELEG March 2025 [RFC9250] Huitema, C., Dickinson, S., and A. Mankin, "DNS over Dedicated QUIC Connections", RFC 9250, DOI 10.17487/RFC9250, May 2022, . [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, . 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 April, et al. Expires 4 September 2025 [Page 6] Internet-Draft DELEG March 2025 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 April, et al. Expires 4 September 2025 [Page 7] Internet-Draft DELEG March 2025 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 April, et al. Expires 4 September 2025 [Page 8]