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

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.¶

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Copyright (c) 2022 IETF Trust and the persons identified as the document authors. All rights reserved.¶

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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.¶

{
    "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/"
        ]
      ]
    ]
}

{
    "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/"
        ]
      ]
    ]
}

{
    "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/"
        ]
      ]
    ]
}