



Network Working Group                                           F. Obser
Internet-Draft                                                  RIPE NCC
Intended status: Informational                              24 June 2025
Expires: 26 December 2025


                 DNS Resolver Information Key for DELEG
                     draft-fobser-resinfo-deleg-00

Abstract

   This document specifies a DNS Resolver Information Key to inform DNS
   clients of DELEG support.

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   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 26 December 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
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Notation . . . . . . . . . . . . . . . . . .   2
   2.  deleg Resolver Information Key  . . . . . . . . . . . . . . .   2
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   2



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   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   5.  Normative References  . . . . . . . . . . . . . . . . . . . .   3
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   3

1.  Introduction

   The Extensible Delegation for DNS [I-D.draft-ietf-deleg] specifies
   the DELEG record type that is authoritative in the parent zone of a
   zone cut.  To prevent downgrade attacks, [I-D.draft-ietf-deleg]
   introduces a new DNSKEY flag.

   A Validating Stub Resolver that is DELEG aware has to know if the
   Recursive Resolver it uses is DELEG aware.  A DELEG aware Recursive
   Resolver using a Forwarder has to know if the Forwarder is DELEG
   aware.

   [RFC9606] specifies a DNS resource record (RR) type RESINFO to allow
   resolvers to publish information about their capabilities and
   policies.  This can be used to inform DNS clients that DELEG is
   supported by the DNS resolver.

1.1.  Requirements Notation

   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.

2.  deleg Resolver Information Key

   deleg:  The presence of this key indicates that the DNS resolver
      supports DELEG.

      A resolver which supports [RFC9606] SHOULD add the deleg key if it
      supports [I-D.draft-ietf-deleg].

      Note that, per the rules for the keys defined in Section 6.4 of
      [RFC6763], if there is no '=' in a key, then it is a boolean
      attribute, simply identified as being present, with no value.

3.  Security Considerations

   The security considerations of [RFC9606] apply.







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4.  IANA Considerations

   The IANA is requested to add the key "deleg", with the description of
   "The presence of the key indicates that DELEG is supported.", and a
   reference to this document.

       +=======+===================================+===============+
       | Name  | Description                       | Reference     |
       +=======+===================================+===============+
       | deleg | The presence of the key indicates | RFC EDITOR:   |
       |       | that DELEG is supported.          | THIS DOCUMENT |
       +-------+-----------------------------------+---------------+

                                  Table 1

5.  Normative References

   [I-D.draft-ietf-deleg]
              April, T., Špaček, P., Weber, R., and Lawrence,
              "Extensible Delegation for DNS", Work in Progress,
              Internet-Draft, draft-ietf-deleg-00, 6 May 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-deleg-
              00>.

   [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>.

   [RFC6763]  Cheshire, S. and M. Krochmal, "DNS-Based Service
              Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
              <https://www.rfc-editor.org/rfc/rfc6763>.

   [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>.

   [RFC9606]  Reddy.K, T. and M. Boucadair, "DNS Resolver Information",
              RFC 9606, DOI 10.17487/RFC9606, June 2024,
              <https://www.rfc-editor.org/rfc/rfc9606>.

Author's Address

   Florian Obser
   RIPE NCC
   Email: florian+ietf@narrans.de





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