dnsop P. Wouters Internet-Draft Aiven Intended status: Standards Track 22 May 2024 Expires: 23 November 2024 Parental Reource Record Types in DNS draft-pwouters-parental-rrtype-00 Abstract This document updates the DNS Parameters' Resource Record (RR) TYPEs registry by adding a field denotating "Parental RRtype" that instructs DNS name servers to store or query RRtypes that have this new field set at the parent side of a delegation instead of at the child side. These DNS protocol rules match those already in use for the Delegation Signer (DS) RRtype. It additonally reserves a small part of the "Reserved for future use" allocation space in the RRtype registry to mark a group of RRtypes values to have this new flag set. The goal of this document is to provide a general facility that future RRtypes can use without requiring to wait a period of many years for DNS implementations and deployments before these type of new RRtype become usable in practise. It is similar in goal to the support of Unknown DNS RRtypes as specified in RFC 3597. This document updates [many things which we should figure out]. 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 23 November 2024. Wouters Expires 23 November 2024 [Page 1] Internet-Draft parental-rrtype May 2024 Copyright Notice Copyright (c) 2024 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 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. Requirements Language . . . . . . . . . . . . . . . . . . 3 1.2. DNS Terminology . . . . . . . . . . . . . . . . . . . . . 3 2. Parental RRtype . . . . . . . . . . . . . . . . . . . . . . . 3 3. Operational Considerations . . . . . . . . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . 3 5. IANA considerations . . . . . . . . . . . . . . . . . . . . . 4 5.1. Registration Table . . . . . . . . . . . . . . . . . . . 4 5.2. RRtype Table . . . . . . . . . . . . . . . . . . . . . . 5 6. Yang Model Update . . . . . . . . . . . . . . . . . . . . . . 5 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 7.1. Normative References . . . . . . . . . . . . . . . . . . 5 7.2. Informative References . . . . . . . . . . . . . . . . . 6 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction The Delegation Signer (DS) Resource Record Type (RRtype) [RFC4034] has the unique property that the record is stored at the parental side of the delegation instead of at the child side. It is currently the only record with this property. As this property was a significant modification of the existing DNS protocol, it took many years for DNS software and DNS deployment to reliably serve and resolve this RRtype. Since then, a number of proposals have surfaces that wanted to create similarly behaving RRtypes. This document updates [DNS RFCs] to generalize this property of resolving at the parental side of a delegation for future RRtypes that fall within a predefined RRtype range. Wouters Expires 23 November 2024 [Page 2] Internet-Draft parental-rrtype May 2024 This document modifies the DNS Parameters' Resource Record (RR) TYPEs registry to reserve 256 RRtypes that have this property. The goal is that a number of years from now, new RRtypes that want to be resolved at the parental side of a delegation can be specified without incurring another time penality for waiting on DNS implementations and deployment updates of DNS authoritative servers and DNS resolver implementations. This uses the same deployment strategy as the Unknown Resource Records [RFC3597]. 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. 1.2. DNS Terminology This document uses DNS Terminology as described in BCP 219 [RFC8499]. 2. Parental RRtype A new property "Parental RRtype" is defined to mean that this RRtype MUST only be resolved at the parental side of a zone delegation. This flag is only set for the existing DS RRtype and a new range of RRtypes specified by this document below. 3. Operational Considerations For Top Level Domains (TLDs), which generally use a Registry, Registrar, Registrant model, it is RECOMMENDED that new Parental RRtypes support a DNS mechanism that allows the introduction, update and deletion of these RRtypes by the DNS Hoster of the child zone. Failing such a mechanism, deployments will still see considerable (seveal years or more) delays in universal deployment of their Parental RRtype. Even though the DNS protool will resolve these records without issue, updates will be required to the EPP protocol [RFC5730] (and its reseller subsystems), Registrar software and deployment and Registrant (enduser) capability of entering such new (possibly complicated) RRtype data into a Registrar website. 4. Security Considerations New Parental RRtypes related to security or privacy SHOULD require DNSSEC [RFC9364], especially if no other trust path (eg WebPKI) is available within the RRdata of the new Parental RRtype. Wouters Expires 23 November 2024 [Page 3] Internet-Draft parental-rrtype May 2024 In general, RRtypes that wish to store data at the parent side of a delegation contains information that is preferably conveyed to the DNS resolver before connecting to the child zone's name servers specified in the NS RRtype of the zone and generally are assumed to increase security and reliability of the DNS. Any future Parental RRtype defined MUST contemplate the security implications of their RRtype getting resolved at the wrong (child) location by old DNS software. If a new Parental RRtype contains security context that the child zone owner would like to confirm it supports (or not), this could be signed by using a new DNSKEY flag, see RFCxxxxx Section yyy. DNS resolvers, especially actively maintained public facing large DNS resolvers, MAY disable those Parental RRtypes values that have not yet been allocated to prevent abuse, with the expectation that once a Parentl RRtype is allocated, that support for these is then promptly enabled. what else ? 5. IANA considerations This document updates the Record Resource (RR) TYPEs IANA Registry listed under the DNS Parameters IANA Registry as follows: This document is added to the Reference section. 5.1. Registration Table The Registration Procedures table is updated as follows: The "Reserved for future use" range is updated to 61696-65279 (0xF100-0xFEFF) Two new entries are added just before the Reserved entry with: Wouters Expires 23 November 2024 [Page 4] Internet-Draft parental-rrtype May 2024 +=============+===============+==========================+==========+ | Decimal | Hex | Registration | Note | | | | Procedures | | +=============+===============+==========================+==========+ | 61440-61680 | 0xF000-0xF0F0 | Expert Review | Parental | | | | (see mailing | RRtypes | | | | list information | | | | | in [RFC6895]) or | | | | | Standards Action | | +-------------+---------------+--------------------------+----------+ | 61681-61695 | 0xF0F1-0xF0FF | | Parental | | | | | RRtypes | | | | | for | | | | | Private | | | | | Use | +-------------+---------------+--------------------------+----------+ Table 1 5.2. RRtype Table A Column "Parental" is added to the second table before the Reference column This colum is populated as follows: RRtype value 43 is set to "YES" All other RRtypes are set to "-" 6. Yang Model Update update RFC 9108 for yang. TODO 7. References 7.1. 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, . [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, . Wouters Expires 23 November 2024 [Page 5] Internet-Draft parental-rrtype May 2024 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC9364] Hoffman, P., "DNS Security Extensions (DNSSEC)", BCP 237, RFC 9364, DOI 10.17487/RFC9364, February 2023, . 7.2. Informative References [RFC3597] Gustafsson, A., "Handling of Unknown DNS Resource Record (RR) Types", RFC 3597, DOI 10.17487/RFC3597, September 2003, . [RFC5730] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)", STD 69, RFC 5730, DOI 10.17487/RFC5730, August 2009, . [RFC8499] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS Terminology", RFC 8499, DOI 10.17487/RFC8499, January 2019, . Appendix A. Acknowledgments The idea of having more than just the DS record resolve at the parent has been suggested a number of times by people in the past. The idea of confirming a zone property to the parent via DNSKEY flag was first proposed by the DELEGATION_ONLY draft. Both were made popular by the DELEG RRtype initiative. This was written before I realised there was a very short scaffolding draft on the same topic: draft-peetterr-dnsop-parent-side-auth-types Author's Address Paul Wouters Aiven Email: paul.wouters@aiven.io Wouters Expires 23 November 2024 [Page 6]