RFC 10037: Registration Data Access Protocol (RDAP) Extension for DNS Time-to-Live (TTL) Values

Status of This Memo

This is an Internet Standards Track document.¶

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.¶

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc10037.¶

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 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.¶

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 RFC 9083 [STD95] 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) values (see Section 5 of [RFC9499]) of those RRsets to be included in responses. Inclusion of these values in RDAP responses (in addition to nameservers, glue IP addresses, and Delegation Signer (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.¶

3. RDAP Response Specification

Servers that support this extension MAY include a "ttl0_data" member in any domain (Section 5.3 of RFC 9083 [STD95]) and nameserver (Section 5.2 of RFC 9083 [STD95]) objects included in RDAP responses. As per Section 2.1 of RFC 9083 [STD95], clients that do not implement this specification SHOULD ignore the "ttl0_data" member.¶

The "ttl0_data" member is an object that has the following members:¶

• A "values" member, which is an object that maps DNS record type mnemonics to TTL values; and¶
• An OPTIONAL "remarks" member, which is an array of remarks (see Section 4.3 of RFC 9083 [STD95]).¶

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" members 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 a valid "ttl0_data" member is provided below. Readers should refer to RFC 9083 [STD95] 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 a valid "ttl0_data" member is provided below.¶

{
  "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."
        ]
      }
    ]
  }
}

4. Operational Considerations

5. IANA Considerations

IANA has registered the following value in the "RDAP Extensions" registry [IANA-RDAP-EXTENSIONS]:¶

Extension Identifier:

ttl0¶

Registry Operator:

Any¶

Specification:

RFC 10037¶

Contact:

IETF <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 RFC 7481 [STD95].¶

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.¶

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, and Éric Vyncke.¶

Author's Address