



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
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   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.











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   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.








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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.






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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 <TBD>
   from the ZONEVERSION TYPE Values space:

          +==================+================+=================+
          | ZONEVERSION TYPE | Mnemonic       | Reference       |
          +==================+================+=================+
          | <TBD>            | 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,
              <https://www.rfc-editor.org/info/rfc2119>.





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   [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>.

   [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,
              <https://www.rfc-editor.org/info/rfc8552>.

   [RFC9660]  Salgado, H., Vergara, M., and D. Wessels, "The DNS Zone
              Version (ZONEVERSION) Option", RFC 9660,
              DOI 10.17487/RFC9660, October 2024,
              <https://www.rfc-editor.org/info/rfc9660>.

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





















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