



Registration Extensions (REGEXT)                                G. Brown
Internet-Draft                                                     ICANN
Intended status: Standards Track                             27 May 2026
Expires: 28 November 2026


            RDAP Extension for DNS Time-To-Live (TTL Values)
                draft-ietf-regext-rdap-ttl-extension-12

Abstract

   This document specifies an extension to the Registration Data Access
   Protocol which allows the Time-To-Live (TTL) values for relevant DNS
   record types to be included in RDAP responses.

About this draft

   This note is to be removed before publishing as an RFC.

   The source for this draft, and an issue tracker, may can be found at
   https://github.com/gbxyz/rdap-ttl-extension.

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 28 November 2026.

Copyright Notice

   Copyright (c) 2026 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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   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
   3.  RDAP Response Specification . . . . . . . . . . . . . . . . .   3
     3.1.  DNS record Types and TTL Values . . . . . . . . . . . . .   5
     3.2.  RDAP Conformance  . . . . . . . . . . . . . . . . . . . .   5
   4.  Operational Considerations  . . . . . . . . . . . . . . . . .   5
     4.1.  RDAP Servers  . . . . . . . . . . . . . . . . . . . . . .   5
     4.2.  RDAP Clients  . . . . . . . . . . . . . . . . . . . . . .   5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   7.  Implementation status . . . . . . . . . . . . . . . . . . . .   6
     7.1.  ICANN RDAP  . . . . . . . . . . . . . . . . . . . . . . .   6
     7.2.  Net::RDAP . . . . . . . . . . . . . . . . . . . . . . . .   7
     7.3.  rdapper . . . . . . . . . . . . . . . . . . . . . . . . .   7
   8.  Change Log  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     8.1.  Changes from 11 to 12 . . . . . . . . . . . . . . . . . .   7
     8.2.  Changes from 10 to 11 . . . . . . . . . . . . . . . . . .   8
     8.3.  Changes from 09 to 10 . . . . . . . . . . . . . . . . . .   8
     8.4.  Changes from 08 to 09 . . . . . . . . . . . . . . . . . .   8
     8.5.  Changes from 07 to 08 . . . . . . . . . . . . . . . . . .   9
     8.6.  Changes from 06 to 07 . . . . . . . . . . . . . . . . . .   9
     8.7.  Changes from 05 to 06 . . . . . . . . . . . . . . . . . .   9
     8.8.  Changes from 04 to 05 . . . . . . . . . . . . . . . . . .   9
     8.9.  Changes from 03 to 04 . . . . . . . . . . . . . . . . . .   9
     8.10. Changes from 02 to 03 . . . . . . . . . . . . . . . . . .   9
     8.11. Changes from 01 to 02 . . . . . . . . . . . . . . . . . .  10
     8.12. Changes from 00 to 01 . . . . . . . . . . . . . . . . . .  10
     8.13. Changes from draft-brown-rdap-ttl-extension-03 to
            draft-ietf-regext-rdap-ttl-extension-00  . . . . . . . .  10
     8.14. Changes from 02 to 03 . . . . . . . . . . . . . . . . . .  10
     8.15. Changes from 01 to 02 . . . . . . . . . . . . . . . . . .  10
     8.16. Changes from 00 to 01 . . . . . . . . . . . . . . . . . .  10
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  11
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  11
     10.2.  Informative References . . . . . . . . . . . . . . . . .  12
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  12







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1.  Introduction

   The Registration Data Access Protocol (RDAP, [STD95]) provides access
   to information about Internet resources (domain names, autonomous
   system numbers, and IP addresses).  While RFC9083 allows RDAP server
   operators to provide information about the content of the NS, DS, A
   and AAAA RRset(s) (see Section 5 of [RFC9499]) which are published in
   the DNS for a given registry object (domain or host object), it does
   not provide a mechanism to allow the Time-To-Live (TTL) (see
   Section 5 of [RFC9499]) values of those RRsets to be included in
   responses.  Inclusion of these values in RDAP responses (in addition
   to nameservers, glue IP addresses, and DS records) allows out-of-band
   debugging of the DNS configuration of troublesome domain names.

   This document describes how TTL information can be included in domain
   and nameserver objects in RDAP responses.  As per Section 5.2 of
   [RFC2181], TTL values are applicable to RRSets rather than individual
   records.

2.  Conventions used in this document

   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.

   This document makes use of the terms defined in Section 1.1 of
   [RFC9083].

3.  RDAP Response Specification

   Servers that support this extension MAY include a "ttl0_data"
   property in any domain (Section 5.3 of [RFC9083]) and nameserver
   (Section 5.2 of [RFC9083]) objects included in RDAP responses.  As
   per Section 2.1 of [RFC9083], clients which do not implement this
   specification SHOULD ignore the "ttl0_data" member.

   The ttl0_data property is an object which has the following
   properties:

   *  A "values" property, which is an object which maps DNS record type
      mnemonics to TTL values;

   *  An OPTIONAL "remarks" property, which is an array of remarks (see
      Section 4.3 of [RFC9083]).





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   As specified in Section 8 of [RFC2181], a TTL value is "an unsigned
   number, with a minimum value of 0, and a maximum value of 2147483647.
   That is, a maximum of 2^31 - 1".  TTL values MUST be represented as
   JSON numbers with no fractional component and no exponent notation.

   The TTL values included in "ttl0_data" properties MUST reflect the
   TTL values as provisioned in the registry database, not the remaining
   TTL of DNS records as observed from live DNS queries.

   An example domain object with valid "ttl0_data" attribute is provided
   below.  Readers should refer to RFC9083 for a description of the
   other objects listed in the example.

   {
     "objectClassName": "domain",
     "rdapConformance": ["rdap_level_0", "ttl0"],
     "ldhName": "domain.example",
     "ttl0_data": {
       "values": {
         "NS": 3600,
         "DS": 300
       },
       "remarks": [
         {
           "description": [
             "For more information about the .example",
             " registry policy relating to DS record TTL changes,",
             "see https://domain.example"
           ],
           "links": [
             {
               "rel": "related",
               "title": ".Example Registry DNS TTL Policy",
               "href": "https://domain.example"
             }
           ]
         }
       ]
     }
   }

   An example nameserver object with valid "ttl0_data" attribute is
   provided below.








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   {
     "objectClassName": "nameserver",
     "rdapConformance": ["rdap_level_0", "ttl0"],
     "ldhName": "ns1.domain.example",
     "ttl0_data": {
       "values": {
         "A": 86400,
         "AAAA": 86400
       },
       "remarks": [
         {
           "description": [
             "The .example registry does not permit TTL ",
             "values for nameservers to be changed."
           ]
         }
       ]
     }
   }

3.1.  DNS record Types and TTL Values

   The DNS record type mnemonics that appear as the property names in
   values objects MUST be in all capitals and MUST be registered with
   IANA in [IANA-RRTYPES].  TTL values MUST be unsigned integers in the
   range 0-2147483647 as per Section 8 of [RFC2181].

3.2.  RDAP Conformance

   Servers returning responses containing TTL values MUST include the
   string "ttl0" in the rdapConformance array.

4.  Operational Considerations

4.1.  RDAP Servers

   This specification is complementary to the Extensible Provisioning
   Protocol [RFC5730] (EPP) Mapping for DNS Time-to-Live (TTL) Values
   [RFC9803], but registry operators do not need to implement that
   extension in their EPP server in order to implement this RDAP
   extension.

4.2.  RDAP Clients

   Many RDAP clients make use of frameworks which automatically
   "hydrate" objects using JSON data received in RDAP responses.  As a
   result, RDAP clients which use these frameworks should explicitly
   carve out the "values" property of "ttl0_data" elements.



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   Since the list of record types appearing in "ttl0_data" elements may
   change with time, clients which implement this extension MUST accept
   responses containing values for all valid DNS record types, and
   SHOULD periodically update the list of valid DNS record types to
   align with [IANA-RRTYPES], to avoid discarding a recently-added
   record type.

5.  IANA Considerations

   IANA has registered the following value in the RDAP Extensions
   Registry [IANA-RDAP-EXTENSIONS]:

   *Extension identifier:* ttl0

   *Registry operator:* Any

   *Published specification:* this document

   *Contact:* IETF <iesg@ietf.org (mailto:iesg@ietf.org)>

   *Intended usage:* this extension describes how DNS TTL values can be
   included in RDAP responses.

6.  Security Considerations

   Security services for the extension specified in this document are
   described in RFC7481.

   This document only concerns itself with the representation of
   configured TTL values for domain and host objects.  The security
   implications of how those TTL values are determined, assigned, or
   modified within a registry system are out of scope.  Readers are
   referred to Section 6 of [RFC9803] for further discussion.

7.  Implementation status

   This section is to be removed before publishing as an RFC.

7.1.  ICANN RDAP

   Organization: ICANN

   Name: ICANN RDAP

   Description: ICANN RDAP contains an RDAP client, server, and common
   libraries.

   Level of maturity: Mature



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   Coverage: All aspects of the protocol are implemented.

   Licensing: Apache License, Version 2.0 or MIT License.

   Contact: globalsupport@icann.org

   URL: https://github.com/icann/icann-rdap

7.2.  Net::RDAP

   Name: Net::RDAP

   Description: An RDAP library for Perl.

   Level of maturity: Mature

   Coverage: All aspects of the protocol are implemented.

   Licensing: Perl (Artistic License or GPL).

   Contact: gavin.brown@fastmail.uk

   URL: https://metacpan.org/pod/Net::RDAP

7.3.  rdapper

   Name: rdapper

   Description: A command-line RDAP client that uses Net::RDAP.

   Level of maturity: Mature

   Coverage: All aspects of the protocol are implemented.

   Licensing: Perl (Artistic License or GPL).

   Contact: gavin.brown@fastmail.uk

   URL: https://metacpan.org/pod/App::rdapper

8.  Change Log

   This section is to be removed before publishing as an RFC.

8.1.  Changes from 11 to 12

   Updates as per IESG evaluation and advice from the RFC Editor:




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   1.  Use a <referencegroup> element to reference [STD95].

   2.  Fix the examples by adding rdapConformacne properties.

   3.  Add type attributes to <sourcecode> elements.

   4.  Changed Section 5 to past tense.

8.2.  Changes from 10 to 11

   Updates as per IESG evaluation:

   1.  Add some context in Section 1 and reference [STD95] (thanks Mike
       Bishop).

   2.  Minor wording changes to Section 6 (thanks Ralf Weber and Mahesh
       Jethanandani).

   3.  Improve readability (thanks Mike Bishop).

   4.  Add sentence to Section 3 clarifying that the TTL values must be
       those stored in the registry database (thanks Mahesh
       Jethanandani).

   5.  Clarify (in Section 3) that JSON numbers representing TTL values
       cannot have fractional or exponent components (thanks Mahesh
       Jethanandani).

   6.  Downgrade one SHOULD to "should" and qualify a SHOULD in
       Section 4.2 (thanks Éric Vyncke).

8.3.  Changes from 09 to 10

   Updates as per IESG evaluation:

   1.  Minor typographic edits.

   2.  Made [RFC9499] a normative reference (thanks Ketan Talaulikar).

8.4.  Changes from 08 to 09

   Updates as per directorate review:

   1.  Improved wording in the last sentence of the first paragraph of
       Section 1.

   2.  Add SHOULD keyword in Section 4.2 to clarify the need to carve
       out the "values" property of "ttl0_data" elements.



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   3.  Updated Section 9.

8.5.  Changes from 07 to 08

   Updates as per AD review:

   1.  Added Section 4.

   2.  Move the last paragraph of Section 1 to Section 4.

   3.  Remove most of Section 3.1, moved some of it to Section 4.

   4.  Backfilled the change log immediately below.

8.6.  Changes from 06 to 07

   1.  Correct reference to [RFC9499].

8.7.  Changes from 05 to 06

   1.  Add missing change log entries to assist in IESG review.

   2.  Added Section 7.

8.8.  Changes from 04 to 05

   1.  Clarify that TTL values are represented using JSON numbers.

8.9.  Changes from 03 to 04

   Updates based on feedback during WGLC:

   1.  Remove the xref in the Abstract to avoid issues when rendered as
       plaintext;

   2.  Refer to RRsets instead of resource records since [RFC2181]
       requires the TTL of all the records in an RRset to be the same;

   3.  Reference [RFC2181] which defines what a TTL is.

   4.  Clarify that clients need to handle (even if to ignore)
       unexpected record types.

8.10.  Changes from 02 to 03

   1.  Switch to array model to object model, based on WG feedback.

   2.  Added Section 9.



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8.11.  Changes from 01 to 02

   1.  Include reference to [IANA-RRTYPES] in Section 3 (thanks Jasdip
       Singh).

   2.  Removed the value member of the link object in the example domain
       object so that it conforms with web linking practice (also thanks
       Jasdip Singh).

8.12.  Changes from 00 to 01

   1.  Updated the extension identifier and extension property name to
       align with the current best practices in
       [I-D.ietf-regext-rdap-extensions].

   2.  Added Section 6.

   3.  Changed MUST to MAY in the first paragraph of Section 3.

   4.  Reduce ambiguity around the repetition of DNS record types in
       responses.

8.13.  Changes from draft-brown-rdap-ttl-extension-03 to draft-ietf-
       regext-rdap-ttl-extension-00

   1.  Name change only.

8.14.  Changes from 02 to 03

   1.  Update reference to [RFC9803].

8.15.  Changes from 01 to 02

   1.  Update reference to the EPP extension.

8.16.  Changes from 00 to 01

   1.  Extension property name renamed to ttl.

   2.  The extension data structure is now an array allowing common TTL
       values, remarks and events to be mapped to multiple DNS record
       types.

   3.  The extension data structure may now include remarks and events.

   4.  Added normative text regarding the value of DNS record mnemonics
       and TTL values.




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9.  Acknowledgements

   The author wishes to thank the following for their constructive
   feedback and advice during the development of this document:

   Andy Newton, Pawel Kowalik, Maarten Wullink, Mohamed Boucadair, Vijay
   K.  Gurbani, Di Ma, Nabeel Cocker, Ketan Talaulikar, Ralf Weber, Mike
   Bishop, Mahesh Jethanandani, Éric Vyncke, Sarah Tarrant.

10.  References

10.1.  Normative References

   [IANA-RDAP-EXTENSIONS]
              IANA, "RDAP Extensions",
              <https://www.iana.org/assignments/rdap-extensions/rdap-
              extensions.xhtml>.

   [IANA-RRTYPES]
              IANA, "Resource Record (RR) TYPEs",
              <https://www.iana.org/assignments/dns-parameters#dns-
              parameters-4>.

   [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>.

   [RFC2181]  Elz, R. and R. Bush, "Clarifications to the DNS
              Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997,
              <https://www.rfc-editor.org/info/rfc2181>.

   [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>.

   [RFC9499]  Hoffman, P. and K. Fujiwara, "DNS Terminology", BCP 219,
              RFC 9499, DOI 10.17487/RFC9499, March 2024,
              <https://www.rfc-editor.org/info/rfc9499>.

   [STD95]    Internet Standard 95,
              <https://www.rfc-editor.org/info/std95/>.
              At the time of writing, this STD comprises the following:

              Newton, A., Ellacott, B., and N. Kong, "HTTP Usage in the
              Registration Data Access Protocol (RDAP)", STD 95,
              RFC 7480, DOI 10.17487/RFC7480, March 2015,
              <https://www.rfc-editor.org/info/rfc7480>.



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              Hollenbeck, S. and N. Kong, "Security Services for the
              Registration Data Access Protocol (RDAP)", STD 95,
              RFC 7481, DOI 10.17487/RFC7481, March 2015,
              <https://www.rfc-editor.org/info/rfc7481>.

              Hollenbeck, S. and A. Newton, "Registration Data Access
              Protocol (RDAP) Query Format", STD 95, RFC 9082,
              DOI 10.17487/RFC9082, June 2021,
              <https://www.rfc-editor.org/info/rfc9082>.

              Hollenbeck, S. and A. Newton, "JSON Responses for the
              Registration Data Access Protocol (RDAP)", STD 95,
              RFC 9083, DOI 10.17487/RFC9083, June 2021,
              <https://www.rfc-editor.org/info/rfc9083>.

              Blanchet, M., "Finding the Authoritative Registration Data
              Access Protocol (RDAP) Service", STD 95, RFC 9224,
              DOI 10.17487/RFC9224, March 2022,
              <https://www.rfc-editor.org/info/rfc9224>.

10.2.  Informative References

   [I-D.ietf-regext-rdap-extensions]
              Newton, A., Singh, J., and T. Harrison, "RDAP Extensions",
              Work in Progress, Internet-Draft, draft-ietf-regext-rdap-
              extensions-12, 18 February 2026,
              <https://datatracker.ietf.org/doc/html/draft-ietf-regext-
              rdap-extensions-12>.

   [RFC5730]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
              STD 69, RFC 5730, DOI 10.17487/RFC5730, August 2009,
              <https://www.rfc-editor.org/info/rfc5730>.

   [RFC9803]  Brown, G., "Extensible Provisioning Protocol (EPP) Mapping
              for DNS Time-to-Live (TTL) Values", RFC 9803,
              DOI 10.17487/RFC9803, June 2025,
              <https://www.rfc-editor.org/info/rfc9803>.

Author's Address

   Gavin Brown
   ICANN
   12025 Waterfront Drive, Suite 300
   Los Angeles, CA 90094-2536
   United States of America
   Email: gavin.brown@icann.org





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