RDAP DNS TTL extension: Registration Data Access Protocol (RDAP) Extension for DNS Time-to-Live (TTL) Values
An RDAP extension that lets registries show the configured DNS TTL values for a domain or nameserver.
Brown, G., "Registration Data Access Protocol (RDAP) Extension for DNS Time-to-Live (TTL) Values", RFC 10037, DOI 10.17487/RFC10037, August 2026, <https://www.rfc-editor.org/info/rfc10037>.
@misc{rfc10037,
series = {Request for Comments},
number = 10037,
howpublished = {RFC 10037},
publisher = {RFC Editor},
doi = {10.17487/RFC10037},
url = {https://www.rfc-editor.org/info/rfc10037},
author = {G. Brown},
title = {{Registration Data Access Protocol (RDAP) Extension for DNS Time-to-Live (TTL) Values}},
pagetotal = 7,
year = 2026,
month = aug,
} RFC text
Contents
Internet Engineering Task Force (IETF) G. Brown
Request for Comments: 10037 ICANN
Category: Standards Track August 2026
ISSN: 2070-1721
Registration Data Access Protocol (RDAP) Extension for DNS Time-to-Live
(TTL) Values
Abstract
This document specifies an extension to the Registration Data Access
Protocol (RDAP), which allows the Time-to-Live (TTL) values for
relevant DNS record types to be included in RDAP responses.
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.
Table of Contents
1. Introduction
2. Conventions Used in This Document
3. RDAP Response Specification
3.1. DNS Record Types and TTL Values
3.2. RDAP Conformance
4. Operational Considerations
4.1. RDAP Servers
4.2. RDAP Clients
5. IANA Considerations
6. Security Considerations
7. References
7.1. Normative References
7.2. Informative References
Acknowledgements
Author's Address
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.
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 uses terms defined in Section 1.1 of RFC 9083 [STD95].
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."
]
}
]
}
}
3.1. DNS Record Types and TTL Values
The DNS record type mnemonics that appear as the member 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 (EPP) [RFC5730] and the EPP Mapping for DNS Time-to-Live
(TTL) Values [RFC9803], but registry operators do not need to
implement that extension in their EPP servers 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 that use these frameworks should explicitly
carve out the "values" member of "ttl0_data" members.
Since the list of record types appearing in "ttl0_data" members may
change with time, clients that 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
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.
7. References
7.1. Normative References
[IANA-RDAP-EXTENSIONS]
IANA, "RDAP Extensions",
<https://www.iana.org/assignments/rdap-extensions>.
[IANA-RRTYPES]
IANA, "Resource Record (RR) TYPEs",
<https://www.iana.org/assignments/dns-parameters>.
[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>.
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>.
7.2. Informative References
[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>.
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
Gavin Brown
ICANN
12025 Waterfront Drive, Suite 300
Los Angeles, CA 90094-2536
United States of America
Email: gavin.brown@icann.org
AI ELI5
On this page
§1Why RDAP Needs TTL Values
The Registration Data Access Protocol (RDAP) gives access to information about domain names, autonomous system numbers and IP addresses. RFC 9083 lets servers describe the content of the NS, DS, A and AAAA RRsets published in the DNS for a registry object, but it has no way to include the Time-to-Live (TTL) of those RRsets.
Adding the TTLs, alongside nameservers, glue IP addresses and Delegation Signer (DS) records, allows out-of-band debugging of the DNS configuration of troublesome domain names. As in RFC 2181, TTLs apply to RRsets rather than to individual records.
The registration card already says who answers questions about a website. It did not say how long people may remember the answer. Now it can.
§3The ttl0_data Member
Servers that support the extension MAY include a ttl0_data member in any domain or nameserver object in an RDAP response. Clients that do not implement the extension SHOULD ignore it.
The member is an object with two parts: a values member that maps DNS record type mnemonics to TTL values, and an OPTIONAL remarks member, which is an array of RDAP remarks.
TTL values MUST be JSON numbers with no fractional component and no exponent notation. The values MUST reflect the TTLs as provisioned in the registry database, not the remaining TTL of records seen in live DNS queries.
It is a little box on the card with two parts: a list saying "this kind of record, this many seconds", and an optional note from the registry.
{
"objectClassName": "nameserver",
"rdapConformance": ["rdap_level_0", "ttl0"],
"ldhName": "ns1.domain.example",
"ttl0_data": {
"values": {
"A": 86400,
"AAAA": 86400
}
}
}§3.1Record Types and TTL Ranges
The member names in values are DNS record type mnemonics. They MUST be in all capitals and MUST be registered with IANA as resource record types.
A TTL MUST be an unsigned integer from 0 to 2147483647, as RFC 2181 defines. A domain example in the RFC carries NS and DS values, and a nameserver example carries A and AAAA values.
Record names are written in capital letters, and the number of seconds cannot be negative or bigger than the largest allowed number.
§3.2Declaring Conformance
Servers returning responses with TTL values MUST include the string ttl0 in the rdapConformance array. That is how a client knows the extension is in use. IANA has registered ttl0 in the RDAP Extensions registry, with registry operator Any.
A response with TTLs must wave a small flag named ttl0 so the reader knows the extra box is there.
§4Notes for Servers and Clients
Servers. The extension complements the Extensible Provisioning Protocol (EPP) and the EPP mapping for DNS TTL values in RFC 9803, but registry operators do not need to implement that EPP extension to implement this one.
Clients. Many RDAP clients use frameworks that automatically "hydrate" objects from JSON, so they should explicitly carve out the values member of ttl0_data. Because the record types may change over time, clients that implement the extension MUST accept values for all valid DNS record types and SHOULD periodically update their list from the IANA registry to avoid discarding a recently added type.
Servers do not need the matching registration-system feature first. Readers should be ready for new kinds of records to show up, rather than throwing away ones they have not seen before.
§6Security Considerations
Security services for the extension are those described in RFC 7481. The document concerns only how configured TTL values for domain and host objects are represented. How a registry determines, assigns or modifies those values is out of scope, and the RFC points readers to Section 6 of RFC 9803 for that discussion.
This note only describes how to show the numbers. It does not say who may change them, which is covered elsewhere.