Finding the Authoritative Registration Data Access Protocol (RDAP) Service
RFC 9224 part of STD 95



Internet Engineering Task Force (IETF)                       M. Blanchet
Request for Comments: 9224                                      Viagenie
STD: 95                                                       March 2022
Obsoletes: 7484                                                         
Category: Standards Track                                               
ISSN: 2070-1721

   Finding the Authoritative Registration Data Access Protocol (RDAP)
                                Service

Abstract

   This document specifies a method to find which Registration Data
   Access Protocol (RDAP) server is authoritative to answer queries for
   a requested scope, such as domain names, IP addresses, or Autonomous
   System numbers.  This document obsoletes RFC 7484.

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/rfc9224.

Copyright Notice

   Copyright (c) 2022 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.  Structure of the RDAP Bootstrap Service Registries
   4.  Bootstrap Service Registry for Domain Name Space
   5.  Bootstrap Service Registries for Internet Numbers
     5.1.  Bootstrap Service Registry for IPv4 Address Space
     5.2.  Bootstrap Service Registry for IPv6 Address Space
     5.3.  Bootstrap Service Registry for AS Number Space
   6.  Entity
   7.  Non-existent Entries or RDAP URL Values
   8.  Deployment and Implementation Considerations
   9.  Limitations
   10. Formal Definition
     10.1.  Imported JSON Terms
     10.2.  Registry Syntax
   11. Security Considerations
   12. IANA Considerations
     12.1.  Bootstrap Service Registry for IPv4 Address Space
     12.2.  Bootstrap Service Registry for IPv6 Address Space
     12.3.  Bootstrap Service Registry for AS Number Space
     12.4.  Bootstrap Service Registry for Domain Name Space
   13. References
     13.1.  Normative References
     13.2.  Informative References
   Appendix A.  Changes since RFC 7484
   Acknowledgements
   Author's Address

1.  Introduction

   Querying and retrieving registration data from registries are defined
   in the Registration Data Access Protocol (RDAP) [RFC7480] [RFC7481]
   [RFC9082] [RFC9083].  These documents do not specify where to send
   the queries.  This document specifies a method to find which server
   is authoritative to answer queries for the requested scope.

   Top-Level Domains (TLDs), Autonomous System (AS) numbers, and network
   blocks are delegated by IANA to Internet registries such as TLD
   registries and Regional Internet Registries (RIRs) that then issue
   further delegations and maintain information about them.  Thus, the
   bootstrap information needed by RDAP clients is best generated from
   data and processes already maintained by IANA; the relevant
   registries already exist at [ipv4reg], [ipv6reg], [asreg], and
   [domainreg].  This document obsoletes [RFC7484].

   Per this document, IANA has created new registries based on a JSON
   format specified in this document, herein named RDAP Bootstrap
   Service Registries.  These new registries are based on the existing
   entries of the above-mentioned registries.  An RDAP client fetches
   the RDAP Bootstrap Service Registries, extracts the data, and then
   performs a match with the query data to find the authoritative
   registration data server and appropriate query base URL.

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.

3.  Structure of the RDAP Bootstrap Service Registries

   The RDAP Bootstrap Service Registries, as specified in Section 12
   below, have been made available as JSON [RFC8259] objects, which can
   be retrieved via HTTP from locations specified by IANA.  The JSON
   object for each registry contains a series of members containing
   metadata about the registry such as a version identifier, a timestamp
   of the publication date of the registry, and a description.
   Additionally, a "services" member contains the registry items
   themselves, as an array.  Each item of the array contains a second-
   level array, with two elements, each of them being a third-level
   array.

   Each element of the Services Array is a second-level array with two
   elements: in order, an Entry Array and a Service URL Array.

   The Entry Array contains all entries that have the same set of base
   RDAP URLs.  The Service URL Array contains the list of base RDAP URLs
   usable for the entries found in the Entry Array.  Elements within
   these two arrays are not ordered in any way.

   An example structure of the JSON output of an RDAP Bootstrap Service
   Registry is illustrated:

   {
       "version": "1.0",
       "publication": "YYYY-MM-DDTHH:MM:SSZ",
       "description": "Some text",
       "services": [
         [
           ["entry1", "entry2", "entry3"],
           [
             "https://registry.example.com/myrdap/",
             "http://registry.example.com/myrdap/"
           ]
         ],
         [
           ["entry4"],
           [
             "https://example.org/"
           ]
         ]
       ]
   }

   The formal syntax is described in Section 10.

   The "version" corresponds to the format version of the registry.
   This specification defines version "1.0".

   The syntax of the "publication" value conforms to the Internet date/
   time format [RFC3339].  The value is the latest update date of the
   registry by IANA.

   The optional "description" string can contain a comment regarding the
   content of the bootstrap object.

   Per [RFC7258], in each array of base RDAP URLs, the secure versions
   of the transport protocol SHOULD be preferred and tried first.  For
   example, if the base RDAP URLs array contains both HTTPS and HTTP
   URLs, the bootstrap client SHOULD try the HTTPS version first.

   Base RDAP URLs MUST have a trailing "/" character because they are
   concatenated to the various segments defined in [RFC9082].

   JSON names MUST follow the format recommendations of Section 6 of
   [RFC7480].  Any unrecognized JSON object properties or values MUST be
   ignored by implementations.

   Internationalized Domain Name labels used as entries or base RDAP
   URLs in the registries defined in this document MUST be only
   represented using their A-label form as defined in [RFC5890].

   All Domain Name labels used as entries or base RDAP URLs in the
   registries defined in this document MUST be only represented in
   lowercase.

4.  Bootstrap Service Registry for Domain Name Space

   The JSON output of this registry contains domain label entries
   attached to the root, grouped by base RDAP URLs, as shown in this
   example.

   {
       "version": "1.0",
       "publication": "2024-01-07T10:11:12Z",
       "description": "Some text",
       "services": [
         [
           ["net", "com"],
           [
             "https://registry.example.com/myrdap/"
           ]
         ],
         [
           ["org", "mytld"],
           [
             "https://example.org/"
           ]
         ],
         [
           ["xn--zckzah"],
           [
             "https://example.net/rdap/xn--zckzah/",
             "http://example.net/rdap/xn--zckzah/"
           ]
         ]
       ]
   }

   The domain name's authoritative registration data service is found by
   doing the label-wise longest match of the target domain name with the
   domain values in the Entry Arrays in the IANA "Bootstrap Service
   Registry for Domain Name Space".  The match is done per label, from
   right to left.  If the longest match results in multiple entries,
   then those entries are considered equivalent.  The values contained
   in the Service URL Array of the matching second-level array are the
   valid base RDAP URLs as described in [RFC9082].

   For example, a domain RDAP query for a.b.example.com matches the com
   entry in one of the arrays of the registry.  The base RDAP URL for
   this query is then taken from the second element of the array, which
   is an array of base RDAP URLs valid for this entry.  The client
   chooses one of the base URLs from this array; in this example, it
   chooses the only one available, "https://registry.example.com/
   myrdap/".  The segment specified in [RFC9082] is then appended to the
   base URL to complete the query.  The complete query is then
   "https://registry.example.com/myrdap/domain/a.b.example.com".

   If a domain RDAP query for a.b.example.com matches both com and
   example.com entries in the registry, then the longest match applies
   and the example.com entry is used by the client.

   If the registry contains entries such as com and goodexample.com,
   then a domain RDAP query for example.com only matches the com entry
   because matching is done on a per-label basis.

   The entry for the root of the domain name space is specified as "".

5.  Bootstrap Service Registries for Internet Numbers

   This section discusses IPv4 and IPv6 address space and Autonomous
   System numbers.

   For IP address space, the authoritative registration data service is
   found by doing a longest match of the target address with the values
   of the arrays in the corresponding RDAP Bootstrap Service Registry
   for Address Space.  The longest match is done the same way as in
   packet forwarding: the addresses are converted in binary form and
   then the binary strings are compared to find the longest match up to
   the specified prefix length.  The values contained in the second
   element of the array are the base RDAP URLs as described in
   [RFC9082].  The longest match method enables covering prefixes of a
   larger address space pointing to one base RDAP URL while more
   specific prefixes within the covering prefix are being served by
   another base RDAP URL.

5.1.  Bootstrap Service Registry for IPv4 Address Space

   The JSON output of this registry contains IPv4 prefix entries,
   specified in Classless Inter-domain Routing (CIDR) format [RFC4632]
   and grouped by RDAP URLs, as shown in this example.

   {
       "version": "1.0",
       "publication": "2024-01-07T10:11:12Z",
       "description": "RDAP Bootstrap file for example registries.",
       "services": [
         [
           ["198.51.100.0/24", "192.0.0.0/8"],
           [
             "https://rir1.example.com/myrdap/"
           ]
         ],
         [
           ["203.0.113.0/24", "192.0.2.0/24"],
           [
             "https://example.org/"
           ]
         ],
         [
           ["203.0.113.0/28"],
           [
             "https://example.net/rdaprir2/",
             "http://example.net/rdaprir2/"
           ]
         ]
       ]
   }

   For example, a query for "192.0.2.1/25" matches the "192.0.0.0/8"
   entry and the "192.0.2.0/24" entry in the example registry above.
   The latter is chosen by the client because it is the longest match.
   The base RDAP URL for this query is then taken from the second
   element of the array, which is an array of base RDAP URLs valid for
   this entry.  The client chooses one of the base URLs from this array;
   in this example, it chooses the only one available,
   "https://example.org/".  The {resource} specified in [RFC9082] is
   then appended to the base URL to complete the query.  The complete
   query is then "https://example.org/ip/192.0.2.1/25".

5.2.  Bootstrap Service Registry for IPv6 Address Space

   The JSON output of this registry contains IPv6 prefix entries, using
   [RFC5952] text representation of the address prefixes format, grouped
   by base RDAP URLs, as shown in this example.

   {
       "version": "1.0",
       "publication": "2024-01-07T10:11:12Z",
       "description": "RDAP Bootstrap file for example registries.",
       "services": [
         [
           ["2001:db8::/34"],
           [
             "https://rir2.example.com/myrdap/"
           ]
         ],
         [
           ["2001:db8:4000::/36", "2001:db8:ffff::/48"],
           [
             "https://example.org/"
           ]
         ],
         [
           ["2001:db8:1000::/36"],
           [
             "https://example.net/rdaprir2/",
             "http://example.net/rdaprir2/"
           ]
         ]
       ]
   }

   For example, a query for "2001:db8:1000::/48" matches the
   "2001:db8::/34" entry and the "2001:db8:1000::/36" entry in the
   example registry above.  The latter is chosen by the client because
   it is the longest match.  The base RDAP URL for this query is then
   taken from the second element of the array, which is an array of base
   RDAP URLs valid for this entry.  The client chooses one of the base
   URLs from this array; in this example, it chooses
   "https://example.net/rdaprir2/" because it's the secure version of
   the protocol.  The segment specified in [RFC9082] is then appended to
   the base URL to complete the query.  The complete query is therefore
   "https://example.net/rdaprir2/ip/2001:db8:1000::/48".  If the target
   RDAP server does not answer, the client can then use another URL
   prefix from the array.

5.3.  Bootstrap Service Registry for AS Number Space

   The JSON output of this registry contains entries for AS number
   ranges, grouped by base RDAP URLs, as shown in this example.  The
   Entry Array is an array containing the list of AS number ranges
   served by the base RDAP URLs found in the second element.  Each
   element of the array contains two AS numbers represented in decimal
   format, separated by a hyphen, that represents the range of AS
   numbers between the two AS numbers (inclusive), where values are in
   increasing order (e.g., 100-200, not 200-100).  A single AS number is
   represented as a range of two identical AS numbers.  AS numbers are
   represented as 'asplain' as defined in [RFC5396].  Ranges MUST NOT
   overlap.

   {
       "version": "1.0",
       "publication": "2024-01-07T10:11:12Z",
       "description": "RDAP Bootstrap file for example registries.",
       "services": [
         [
           ["64496-64496"],
           [
             "https://rir3.example.com/myrdap/"
           ]
         ],
         [
           ["64497-64510", "65536-65551"],
           [
             "https://example.org/"
           ]
         ],
         [
           ["64512-65534"],
           [
             "http://example.net/rdaprir2/",
             "https://example.net/rdaprir2/"
           ]
         ]
       ]
   }

   For example, a query for AS 65411 matches the 64512-65534 entry in
   the example registry above.  The base RDAP URL for this query is then
   taken from the second element of the array, which is an array of base
   RDAP URLs valid for this entry.  The client chooses one of the base
   URLs from this array; in this example, it chooses
   "https://example.net/rdaprir2/".  The segment specified in [RFC9082]
   is then appended to the base URL to complete the query.  The complete
   query is, therefore, "https://example.net/rdaprir2/autnum/65411".  If
   the server does not answer, the client can then use another URL
   prefix from the array.

6.  Entity

   Entities (such as contacts, registrants, or registrars) can be
   queried by handle as described in [RFC9082].  Since there is no
   global name space for entities, this document does not describe how
   to find the authoritative RDAP server for entities.  However, it is
   possible that, if the entity identifier was received from a previous
   query, the same RDAP server could be queried for that entity, or the
   entity identifier itself is a fully qualified URL that can be
   queried.  The mechanism described in [RFC8521] MAY also be used.

7.  Non-existent Entries or RDAP URL Values

   The registries may not contain the requested value.  In these cases,
   there is no known RDAP server for that requested value, and the
   client SHOULD provide an appropriate error message to the user.

8.  Deployment and Implementation Considerations

   This method relies on the fact that RDAP clients are fetching the
   IANA registries to then find the servers locally.  Clients SHOULD NOT
   fetch the registry on every RDAP request.  Clients SHOULD cache the
   registry, but use underlying protocol signaling, such as the HTTP
   Expires header field [RFC7234], to identify when it is time to
   refresh the cached registry.

   Some authorities of registration data may work together on sharing
   their information for a common service, including mutual redirection
   [REDIRECT-RDAP].

   When a new object is allocated, such as a new AS range, a new TLD, or
   a new IP address range, there is no guarantee that this new object
   will have an entry in the corresponding bootstrap RDAP registry,
   since the setup of the RDAP server for this new entry may become live
   and registered later.  Therefore, the clients should expect that even
   if an object, such as TLD, IP address range, or AS range is
   allocated, the existence of the entry in the corresponding bootstrap
   registry is not guaranteed.

9.  Limitations

   This method does not provide a direct way to find authoritative RDAP
   servers for any other objects than the ones described in this
   document.  In particular, the following objects are not bootstrapped
   with the method described in this document:

   *  entities

   *  queries using search patterns that do not contain a terminating
      string that matches some entries in the registries

   *  nameservers

   *  help

10.  Formal Definition

   This section is the formal definition of the registries.  The
   structure of JSON objects and arrays using a set of primitive
   elements is defined in [RFC8259].  Those elements are used to
   describe the JSON structure of the registries.

10.1.  Imported JSON Terms

   OBJECT:  a JSON object, defined in Section 4 of [RFC8259]

   MEMBER:  a member of a JSON object, defined in Section 4 of [RFC8259]

   MEMBER-NAME:  the name of a MEMBER, defined as a "string" in
      Section 4 of [RFC8259]

   MEMBER-VALUE:  the value of a MEMBER, defined as a "value" in
      Section 4 of [RFC8259]

   ARRAY:  an array, defined in Section 5 of [RFC8259]

   ARRAY-VALUE:  an element of an ARRAY, defined in Section 5 of
      [RFC8259]

   STRING:  a "string", as defined in Section 7 of [RFC8259]

10.2.  Registry Syntax

   Using the above terms for the JSON structures, the syntax of a
   registry is defined as follows:

   rdap-bootstrap-registry:  an OBJECT containing a MEMBER version and a
      MEMBER publication, an optional MEMBER description, and a MEMBER
      services-list

   version:  a MEMBER with MEMBER-NAME "version" and MEMBER-VALUE a
      STRING

   publication:  a MEMBER with MEMBER-NAME "publication" and MEMBER-
      VALUE a STRING

   description:  a MEMBER with MEMBER-NAME "description" and MEMBER-
      VALUE a STRING

   services-list:  a MEMBER with MEMBER-NAME "services" and MEMBER-VALUE
      a services-array

   services-array:  an ARRAY, where each ARRAY-VALUE is a service

   service:  an ARRAY of 2 elements, where the first ARRAY-VALUE is an
      entry-list and the second ARRAY-VALUE is a service-uri-list

   entry-list:  an ARRAY, where each ARRAY-VALUE is an entry

   entry:  a STRING

   service-uri-list:  an ARRAY, where each ARRAY-VALUE is a service-uri

   service-uri:  a STRING

11.  Security Considerations

   By providing a bootstrap method to find RDAP servers, this document
   helps to ensure that the end users will get the RDAP data from an
   authoritative source instead of from rogue sources.  The method has
   the same security properties as the RDAP protocols themselves.  The
   transport used to access the registries uses TLS [RFC8446].

   Additional considerations on using RDAP are described in [RFC7481].

12.  IANA Considerations

   IANA has created the RDAP Bootstrap Services Registries listed below
   and made them available as JSON objects.  The contents of these
   registries are described in Sections 3, 4, and 5, with the formal
   syntax specified in Section 10.  The registries MUST be accessible
   only through HTTPS (TLS [RFC8446]) transport.

   The process for adding or updating entries in these registries
   differs from the normal IANA registry processes: these registries are
   generated from the data, processes, and policies maintained by IANA
   in their allocation registries ([ipv4reg], [ipv6reg], [asreg], and
   [domainreg]), with the addition of new RDAP server information.

   IANA updates RDAP Bootstrap Services Registries entries from the
   allocation registries as those registries are updated.

   This document does not change any policies related to the allocation
   registries; IANA has provided a mechanism for collecting the RDAP
   server information.

   IANA has created a new top-level category on the Protocol Registries
   page: <https://www.iana.org/protocols>.  The group is called
   "Registration Data Access Protocol (RDAP)".  Each of the RDAP
   Bootstrap Services Registries has been made available for on-demand
   download in the JSON format by the general public, and that
   registry's URI is listed directly on the Protocol Registries page.

   Other normal registries will be added to this group by other
   documents, but the reason the URIs for these registries are clearly
   listed on the main page is to make those URIs obvious to implementers
   -- these are registries that will be accessed by software, as well as
   by humans using them for reference information.

   Because these registries will be accessed by software, the download
   demand for the RDAP Bootstrap Services Registries may be unusually
   high compared to normal IANA registries.  The technical
   infrastructure by which registries are published has been put in
   place by IANA to support the load.  Since the publication of
   [RFC7484], no issues have been reported regarding the load or the
   service.

   As discussed in Section 8, software that accesses these registries
   will depend on the HTTP Expires header field to limit their query
   rate.  It is, therefore, important for that header field to be
   properly set to provide timely information as the registries change,
   while maintaining a reasonable load on the IANA servers.

   The HTTP Content-Type returned to clients accessing these JSON-
   formatted registries MUST be "application/json", as defined in
   [RFC8259].

   Because of how information in the RDAP Bootstrap Services Registries
   is grouped and formatted, the registry entries may not be sortable.
   It is, therefore, not required or expected that the entries be
   ordered in any way.

12.1.  Bootstrap Service Registry for IPv4 Address Space

   Entries in this registry contain at least the following:

   *  a CIDR [RFC4632] specification of the network block being
      registered

   *  one or more URLs that provide the RDAP service regarding this
      registration

12.2.  Bootstrap Service Registry for IPv6 Address Space

   Entries in this registry contain at least the following:

   *  an IPv6 prefix [RFC5952] specification of the network block being
      registered

   *  one or more URLs that provide the RDAP service regarding this
      registration

12.3.  Bootstrap Service Registry for AS Number Space

   Entries in this registry contain at least the following:

   *  a range of Autonomous System numbers being registered

   *  one or more URLs that provide the RDAP service regarding this
      registration

12.4.  Bootstrap Service Registry for Domain Name Space

   Entries in this registry contain at least the following:

   *  a domain name attached to the root being registered

   *  one or more URLs that provide the RDAP service regarding this
      registration

13.  References

13.1.  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>.

   [RFC3339]  Klyne, G. and C. Newman, "Date and Time on the Internet:
              Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
              <https://www.rfc-editor.org/info/rfc3339>.

   [RFC4632]  Fuller, V. and T. Li, "Classless Inter-domain Routing
              (CIDR): The Internet Address Assignment and Aggregation
              Plan", BCP 122, RFC 4632, DOI 10.17487/RFC4632, August
              2006, <https://www.rfc-editor.org/info/rfc4632>.

   [RFC5396]  Huston, G. and G. Michaelson, "Textual Representation of
              Autonomous System (AS) Numbers", RFC 5396,
              DOI 10.17487/RFC5396, December 2008,
              <https://www.rfc-editor.org/info/rfc5396>.

   [RFC5890]  Klensin, J., "Internationalized Domain Names for
              Applications (IDNA): Definitions and Document Framework",
              RFC 5890, DOI 10.17487/RFC5890, August 2010,
              <https://www.rfc-editor.org/info/rfc5890>.

   [RFC5952]  Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
              Address Text Representation", RFC 5952,
              DOI 10.17487/RFC5952, August 2010,
              <https://www.rfc-editor.org/info/rfc5952>.

   [RFC7258]  Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
              Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May
              2014, <https://www.rfc-editor.org/info/rfc7258>.

   [RFC7480]  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>.

   [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>.

   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", STD 90, RFC 8259,
              DOI 10.17487/RFC8259, December 2017,
              <https://www.rfc-editor.org/info/rfc8259>.

13.2.  Informative References

   [asreg]    IANA, "Autonomous System (AS) Numbers",
              <https://www.iana.org/assignments/as-numbers>.

   [domainreg]
              IANA, "Root Zone Database",
              <https://www.iana.org/domains/root/db>.

   [ipv4reg]  IANA, "IANA IPv4 Address Space Registry",
              <https://www.iana.org/assignments/ipv4-address-space>.

   [ipv6reg]  IANA, "IPv6 Global Unicast Address Assignments",
              <https://www.iana.org/assignments/ipv6-unicast-address-
              assignments>.

   [REDIRECT-RDAP]
              Martinez, C.M., Ed., Zhou, L., Ed., and G. Rada,
              "Redirection Service for Registration Data Access
              Protocol", Work in Progress, Internet-Draft, draft-ietf-
              weirds-redirects-04, July 2014,
              <https://datatracker.ietf.org/doc/html/draft-ietf-weirds-
              redirects-04>.

   [RFC7071]  Borenstein, N. and M. Kucherawy, "A Media Type for
              Reputation Interchange", RFC 7071, DOI 10.17487/RFC7071,
              November 2013, <https://www.rfc-editor.org/info/rfc7071>.

   [RFC7234]  Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
              Ed., "Hypertext Transfer Protocol (HTTP/1.1): Caching",
              RFC 7234, DOI 10.17487/RFC7234, June 2014,
              <https://www.rfc-editor.org/info/rfc7234>.

   [RFC7481]  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>.

   [RFC7484]  Blanchet, M., "Finding the Authoritative Registration Data
              (RDAP) Service", RFC 7484, DOI 10.17487/RFC7484, March
              2015, <https://www.rfc-editor.org/info/rfc7484>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

   [RFC8521]  Hollenbeck, S. and A. Newton, "Registration Data Access
              Protocol (RDAP) Object Tagging", BCP 221, RFC 8521,
              DOI 10.17487/RFC8521, November 2018,
              <https://www.rfc-editor.org/info/rfc8521>.

   [RFC9082]  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>.

   [RFC9083]  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>.

Appendix A.  Changes since RFC 7484

   There are no substantive changes except for minor clarifications.
   This update is primarily to meet the requirements for moving to an
   Internet Standard.

Acknowledgements

   The WEIRDS Working Group had multiple discussions on this topic,
   including a session during IETF 84, where various methods such as in-
   DNS and others were debated.  The idea of using IANA registries was
   discovered by the author during discussions with his colleagues as
   well as by a comment from Andy Newton.  All the people involved in
   these discussions are herein acknowledged.  Linlin Zhou, Jean-
   Philippe Dionne, John Levine, Kim Davies, Ernie Dainow, Scott
   Hollenbeck, Arturo Servin, Andy Newton, Murray Kucherawy, Tom
   Harrison, Naoki Kambe, Alexander Mayrhofer, Edward Lewis, Pete
   Resnick, Alessandro Vesely, Bert Greevenbosch, Barry Leiba, Jari
   Arkko, Kathleen Moriaty, Stephen Farrell, Richard Barnes, and Jean-
   Francois Tremblay provided input and suggestions to the first version
   of this document.

   Guillaume Leclanche was a coauthor of this document for some
   revisions; his support is therein acknowledged and greatly
   appreciated.  The section on formal definition was inspired by
   Section 6.2 of [RFC7071].  This new version [This document] received
   comments and suggestions from Gavin Brown, Patrick Mevzek, John
   Levine, Jasdip Singh, George Michaelson, Scott Hollenbeck, Russ
   Housley, Joel Halpern, Lars Eggert, Benjamin Kaduk, Scott Kelly, Éric
   Vyncke, John Scudder, Erik Kline, and Robert Wilton.  Errata for RFC
   7484 were submitted by Pieter Vandepitte and were applied to this
   document.

Author's Address

   Marc Blanchet
   Viagenie
   246 Aberdeen
   Quebec QC G1R 2E1
   Canada
   Email: [email protected]
   URI:   https://viagenie.ca