DNSOP S.W.J. Ubbink Internet-Draft SIDN Intended status: Standards Track 13 October 2025 Expires: 16 April 2026 DNS Backend Serial Zone Version Option draft-ubbink-dnsop-backend-serial-zoneversion-00 Abstract The DNS Backend Serial Zone Version Opion is a way to get information about the version of a DNS zone in the backend. For example when a DNSSEC signer for a zone generates a new SOA serial, because it has created new RRSIG records, the original data has not changed, but this is not visible to anyone looking at the zone via DNS. This document will make it possible to show the zone information which is the source of the presented data. 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 16 April 2026. Copyright Notice Copyright (c) 2025 IETF Trust and the persons identified as the document authors. All rights reserved. Ubbink Expires 16 April 2026 [Page 1] Internet-Draft dns-backend-zoneversion October 2025 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. Discussion Venues . . . . . . . . . . . . . . . . . . . . . . 2 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Terminology and Definitions . . . . . . . . . . . . . . . . . 3 4. Relation to the ZONEVERSION option . . . . . . . . . . . . . 3 5. The backend serial in the zone . . . . . . . . . . . . . . . 3 6. The backend serial ZONEVERSION type . . . . . . . . . . . . . 3 7. Security Considerations . . . . . . . . . . . . . . . . . . . 4 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 8.1. ZONEVERSION TYPE value . . . . . . . . . . . . . . . . . 4 8.2. _backend-version Underscore Name . . . . . . . . . . . . 4 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 10. Normative References . . . . . . . . . . . . . . . . . . . . 4 Appendix A. Change History (to be removed before publication) . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Discussion Venues This note is to be removed before publishing as an RFC. Source for this draft and an issue tracker can be found at https://github.com/SIDN/ietf-zoneversion-extended.git (https://github.com/SIDN/ietf-zoneversion-extended.git) . 2. Introduction The DNS Backend Serial Zone Version Option is a way to get information about the version of a DNS zone in the backend. For example when a DNSSEC signer for a zone generates a new SOA serial, because it has created new RRSIG records, the original data has not changed, but this is not visible to anyone looking at the zone. This document makes it possible to retreive the backend version that is the source of data in the DNS response. Ubbink Expires 16 April 2026 [Page 2] Internet-Draft dns-backend-zoneversion October 2025 3. Terminology and Definitions 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. 4. Relation to the ZONEVERSION option This document extends the original DNS Zone version Option [!@RFC9660] to include an extra ZONEVERSION type. 5. The backend serial in the zone To make the backend serial available in the ZONEVERSION, it must be available in the zone itself. Because creating an out of bound solution would be to much work. This document defines a label where the backend serial will be available to be used in the ZONEVERSION. The backend serial will be published in a _backend-version label under the zone apex. For example: _backend-version.example.nl IN TXT "2025101099" The setting of the value of the _backend-version label is out of scope for this document. The RDATA is not limited to a 32-bit number, like the SOA-SERIAL. It can be any string. There MUST only be one _backend-version label. 6. The backend serial ZONEVERSION type This document defines a new ZONEVERSION option TYPE, which can be constructed from RDATA in the zone. The mnemonic for this type is "BACKEND-SERIAL". The VERSION value for the BACKEND-SERIAL type MUST come from the RDATA of the _backend-version label in the zone. Unless the software already knows the backend serial, then it SHOULD use that. If there are multiple _backend-version labels at the zone apex, these MUST all be ignored. Ubbink Expires 16 April 2026 [Page 3] Internet-Draft dns-backend-zoneversion October 2025 7. Security Considerations When using the backend serial zoneversion option it will reveal a small bit of information of your backend to the world. This should be a consius decission. 8. IANA Considerations 8.1. ZONEVERSION TYPE value This document defines a new item for the ZONEVERSION TYPE option, entitled BACKEND-SERIAL (see Section 6), and assigns a value of from the ZONEVERSION TYPE Values space: +==================+================+=================+ | ZONEVERSION TYPE | Mnemonic | Reference | +==================+================+=================+ | | BACKEND-SERIAL | [this document] | +------------------+----------------+-----------------+ Table 1 8.2. _backend-version Underscore Name Per [RFC8552], IANA is requested to add the following entries to the "Underscored and Globally Scoped DNS Node Names" registry: +=========+==================+=================+ | RR Type | _NODE NAME | Reference | +=========+==================+=================+ | TXT | _backend-version | [this document] | +---------+------------------+-----------------+ Table 2 9. Acknowledgements Many thanks to original authors of [RFC9660]. And the following reviewers: Peter van Dijk. 10. 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, . Ubbink Expires 16 April 2026 [Page 4] Internet-Draft dns-backend-zoneversion October 2025 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8552] Crocker, D., "Scoped Interpretation of DNS Resource Records through "Underscored" Naming of Attribute Leaves", BCP 222, RFC 8552, DOI 10.17487/RFC8552, March 2019, . [RFC9660] Salgado, H., Vergara, M., and D. Wessels, "The DNS Zone Version (ZONEVERSION) Option", RFC 9660, DOI 10.17487/RFC9660, October 2024, . Appendix A. Change History (to be removed before publication) * draft-ubbink-dnsop-backend-serial-zoneversion-00 | Use a better name for the draft. Use a different label for the | backend version. Add security considerations * draft-ubbink-zoneversion... | Initial publication Author's Address Stefan Ubbink SIDN Email: stefan.ubbink@sidn.nl Ubbink Expires 16 April 2026 [Page 5]