7480
INTERNET STANDARD
HTTP Usage in the Registration Data Access Protocol (RDAP)
Authors: A. Newton, B. Ellacott, N. Kong
Date: March 2015
Area: app
Working Group: weirds
Stream: IETF
Abstract
This document is one of a collection that together describes the Registration Data Access Protocol (RDAP). It describes how RDAP is transported using the Hypertext Transfer Protocol (HTTP). RDAP is a successor protocol to the very old WHOIS protocol. The purpose of this document is to clarify the use of standard HTTP mechanisms for this application.
RFC 7480
INTERNET STANDARD
Internet Engineering Task Force (IETF) A. Newton
Request for Comments: 7480 ARIN
Category: Standards Track B. Ellacott
ISSN: 2070-1721 APNIC
N. Kong
CNNIC
March 2015
<span class="h1">HTTP Usage in the Registration Data Access Protocol (RDAP)</span>
Abstract
This document is one of a collection that together describes the
Registration Data Access Protocol (RDAP). It describes how RDAP is
transported using the Hypertext Transfer Protocol (HTTP). RDAP is a
successor protocol to the very old WHOIS protocol. The purpose of
this document is to clarify the use of standard HTTP mechanisms for
this application.
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 <a href="./rfc5741#section-2">Section 2 of RFC 5741</a>.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
<a href="https://www.rfc-editor.org/info/rfc7480">http://www.rfc-editor.org/info/rfc7480</a>.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to <a href="https://www.rfc-editor.org/bcp/bcp78">BCP 78</a> and the IETF Trust's Legal
Provisions Relating to IETF Documents
(<a href="http://trustee.ietf.org/license-info">http://trustee.ietf.org/license-info</a>) 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 Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
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Table of Contents
<a href="#section-1">1</a>. Introduction . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-2">2</a>
<a href="#section-2">2</a>. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-4">4</a>
<a href="#section-3">3</a>. Design Intents . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-5">5</a>
<a href="#section-4">4</a>. Queries . . . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-5">5</a>
<a href="#section-4.1">4.1</a>. HTTP Methods . . . . . . . . . . . . . . . . . . . . . . <a href="#page-5">5</a>
<a href="#section-4.2">4.2</a>. Accept Header . . . . . . . . . . . . . . . . . . . . . . <a href="#page-5">5</a>
<a href="#section-4.3">4.3</a>. Query Parameters . . . . . . . . . . . . . . . . . . . . <a href="#page-6">6</a>
<a href="#section-5">5</a>. Types of HTTP Response . . . . . . . . . . . . . . . . . . . <a href="#page-6">6</a>
<a href="#section-5.1">5.1</a>. Positive Answers . . . . . . . . . . . . . . . . . . . . <a href="#page-6">6</a>
<a href="#section-5.2">5.2</a>. Redirects . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-6">6</a>
<a href="#section-5.3">5.3</a>. Negative Answers . . . . . . . . . . . . . . . . . . . . <a href="#page-7">7</a>
<a href="#section-5.4">5.4</a>. Malformed Queries . . . . . . . . . . . . . . . . . . . . <a href="#page-7">7</a>
<a href="#section-5.5">5.5</a>. Rate Limits . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-7">7</a>
<a href="#section-5.6">5.6</a>. Cross-Origin Resource Sharing (CORS) . . . . . . . . . . <a href="#page-8">8</a>
<a href="#section-6">6</a>. Extensibility . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-8">8</a>
<a href="#section-7">7</a>. Security Considerations . . . . . . . . . . . . . . . . . . . <a href="#page-9">9</a>
<a href="#section-8">8</a>. IANA Considerations . . . . . . . . . . . . . . . . . . . . . <a href="#page-9">9</a>
<a href="#section-8.1">8.1</a>. RDAP Extensions Registry . . . . . . . . . . . . . . . . <a href="#page-9">9</a>
<a href="#section-9">9</a>. Internationalization Considerations . . . . . . . . . . . . . <a href="#page-10">10</a>
<a href="#section-9.1">9.1</a>. URIs and IRIs . . . . . . . . . . . . . . . . . . . . . . <a href="#page-10">10</a>
<a href="#section-9.2">9.2</a>. Language Identifiers in Queries and Responses . . . . . . <a href="#page-10">10</a>
<a href="#section-9.3">9.3</a>. Language Identifiers in HTTP Headers . . . . . . . . . . <a href="#page-10">10</a>
<a href="#section-10">10</a>. References . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-11">11</a>
<a href="#section-10.1">10.1</a>. Normative References . . . . . . . . . . . . . . . . . . <a href="#page-11">11</a>
<a href="#section-10.2">10.2</a>. Informative References . . . . . . . . . . . . . . . . . <a href="#page-12">12</a>
<a href="#appendix-A">Appendix A</a>. Protocol Example . . . . . . . . . . . . . . . . . . <a href="#page-13">13</a>
<a href="#appendix-B">Appendix B</a>. Cache Busting . . . . . . . . . . . . . . . . . . . <a href="#page-13">13</a>
<a href="#appendix-C">Appendix C</a>. Bootstrapping and Redirection . . . . . . . . . . . <a href="#page-14">14</a>
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-15">15</a>
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . <a href="#page-16">16</a>
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<span class="h2"><a class="selflink" id="section-1" href="#section-1">1</a>. Introduction</span>
This document describes the usage of the Hypertext Transfer Protocol
(HTTP) [<a href="./rfc7230" title=""Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing"">RFC7230</a>] for the Registration Data Access Protocol (RDAP).
The goal of this document is to tie together usage patterns of HTTP
into a common profile applicable to the various types of directory
services serving registration data using practices informed by the
Representational State Transfer (REST) [<a href="#ref-REST" title=""Principled Design of the Modern Web Architecture"">REST</a>] architectural style.
By giving the various directory services common behavior, a single
client is better able to retrieve data from directory services
adhering to this behavior.
Registration data expected to be presented by this service is
Internet resource registration data -- registration of domain names
and Internet number resources. This data is typically provided by
WHOIS [<a href="./rfc3912" title=""WHOIS Protocol Specification"">RFC3912</a>] services, but the WHOIS protocol is insufficient to
modern registration data service requirements. A replacement
protocol is expected to retain the simple transactional nature of
WHOIS, while providing a specification for queries and responses,
redirection to authoritative sources, support for Internationalized
Domain Names (IDNs) [<a href="./rfc5890" title=""Internationalized Domain Names for Applications (IDNA): Definitions and Document Framework"">RFC5890</a>], and support for localized registration
data such as addresses and organization or person names.
In designing these common usage patterns, this document introduces
considerations for a simple use of HTTP. Where complexity may
reside, it is the goal of this document to place it upon the server
and to keep the client as simple as possible. A client
implementation should be possible using common operating system
scripting tools (e.g., bash and wget).
This is the basic usage pattern for this protocol:
1. A client determines an appropriate server to query along with the
appropriate base Uniform Resource Locator (URL) to use in such
queries. [<a href="./rfc7484" title=""Finding the Authoritative Registration Data (RDAP) Service"">RFC7484</a>] describes one method to determine the server
and the base URL. See <a href="#appendix-C">Appendix C</a> for more information.
2. A client issues an HTTP (or HTTPS) query using GET [<a href="./rfc7231" title=""Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content"">RFC7231</a>]. As
an example, a query URL for the network registration 192.0.2.0
might be
http://example.com/rdap/ip/192.0.2.0
[<a id="ref-RFC7482">RFC7482</a>] details the various queries used in RDAP.
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3. If the receiving server has the information for the query, it
examines the Accept header field of the query and returns a 200
response with a response entity appropriate for the requested
format. [<a href="./rfc7483" title=""JSON Responses for the Registration Data Access Protocol (RDAP)"">RFC7483</a>] details a response in JavaScript Object
Notation (JSON).
4. If the receiving server does not have the information for the
query but does have knowledge of where the information can be
found, it will return a redirection response (3xx) with the
Location header field containing an HTTP(S) URL pointing to the
information or another server known to have knowledge of the
location of the information. The client is expected to requery
using that HTTP URL.
5. If the receiving server does not have the information being
requested and does not have knowledge of where the information
can be found, it returns a 404 response.
6. If the receiving server will not answer a request for policy
reasons, it will return an error response (4xx) indicating the
reason for giving no answer.
It is not the intent of this document to redefine the meaning and
semantics of HTTP. The purpose of this document is to clarify the
use of standard HTTP mechanisms for this application.
<span class="h2"><a class="selflink" id="section-2" href="#section-2">2</a>. Terminology</span>
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [<a href="./rfc2119" title=""Key words for use in RFCs to Indicate Requirement Levels"">RFC2119</a>].
As is noted in "Security and Stability Advisory Committee (SSAC)
Report on WHOIS Terminology and Structure" [<a href="#ref-SAC-051" title=""SSAC Report on Domain Name WHOIS Terminology and Structure"">SAC-051</a>], the term
"WHOIS" is overloaded, often referring to a protocol, a service, and
data. In accordance with [<a href="#ref-SAC-051" title=""SSAC Report on Domain Name WHOIS Terminology and Structure"">SAC-051</a>], this document describes the base
behavior for an RDAP. [<a href="#ref-SAC-051" title=""SSAC Report on Domain Name WHOIS Terminology and Structure"">SAC-051</a>] describes a protocol profile of RDAP
for Domain Name Registries (DNRs), the Domain Name Registration Data
Access Protocol (DNRD-AP).
In this document, an RDAP client is an HTTP user agent performing an
RDAP query, and an RDAP server is an HTTP server providing an RDAP
response. RDAP query and response formats are described in [<a href="./rfc7482" title=""Registration Data Access Protocol (RDAP) Query Format"">RFC7482</a>]
and [<a href="./rfc7483" title=""JSON Responses for the Registration Data Access Protocol (RDAP)"">RFC7483</a>], while this document describes how RDAP clients and
servers use HTTP to exchange queries and responses. [<a href="./rfc7481" title=""Security Services for the Registration Data Access Protocol (RDAP)"">RFC7481</a>]
describes security considerations for RDAP.
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<span class="h2"><a class="selflink" id="section-3" href="#section-3">3</a>. Design Intents</span>
There are a few design criteria this document attempts to meet.
First, each query is meant to require only one path of execution to
obtain an answer. A response may contain an answer, no answer, or a
redirect, and clients are not expected to fork multiple paths of
execution to make a query.
Second, the semantics of the request/response allow for future and/or
non-standard response formats. In this document, only a JSON
[<a href="./rfc7159" title=""The JavaScript Object Notation (JSON) Data Interchange Format"">RFC7159</a>] response media type is noted, with the response contents to
be described separately (see [<a href="./rfc7483" title=""JSON Responses for the Registration Data Access Protocol (RDAP)"">RFC7483</a>]). This document only
describes how RDAP is transported using HTTP with this format.
Third, this protocol is intended to be able to make use of the range
of mechanisms available for use with HTTP. HTTP offers a number of
mechanisms not described further in this document. Operators are
able to make use of these mechanisms according to their local policy,
including cache control, authorization, compression, and redirection.
HTTP also benefits from widespread investment in scalability,
reliability, and performance, as well as widespread programmer
understanding of client behaviors for web services styled after REST
[<a href="#ref-REST" title=""Principled Design of the Modern Web Architecture"">REST</a>], reducing the cost to deploy Registration Data Directory
Services and clients. This protocol is forward compatible with HTTP
2.0.
<span class="h2"><a class="selflink" id="section-4" href="#section-4">4</a>. Queries</span>
<span class="h3"><a class="selflink" id="section-4.1" href="#section-4.1">4.1</a>. HTTP Methods</span>
Clients use the GET method to retrieve a response body and use the
HEAD method to determine existence of data on the server. Clients
SHOULD use either the HTTP GET or HEAD methods (see [<a href="./rfc7231" title=""Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content"">RFC7231</a>]).
Servers are under no obligation to support other HTTP methods;
therefore, clients using other methods will likely not interoperate
properly.
Clients and servers MUST support HTTPS to support security services.
<span class="h3"><a class="selflink" id="section-4.2" href="#section-4.2">4.2</a>. Accept Header</span>
To indicate to servers that an RDAP response is desired, clients
include an Accept header field with an RDAP-specific JSON media type,
the generic JSON media type, or both. Servers receiving an RDAP
request return an entity with a Content-Type header containing the
RDAP-specific JSON media type.
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This specification does not define the responses a server returns to
a request with any other media types in the Accept header field, or
with no Accept header field. One possibility would be to return a
response in a media type suitable for rendering in a web browser.
<span class="h3"><a class="selflink" id="section-4.3" href="#section-4.3">4.3</a>. Query Parameters</span>
Servers MUST ignore unknown query parameters. Use of unknown query
parameters for cache busting is described in <a href="#appendix-B">Appendix B</a>.
<span class="h2"><a class="selflink" id="section-5" href="#section-5">5</a>. Types of HTTP Response</span>
This section describes the various types of responses a server may
send to a client. While no standard HTTP response code is forbidden
in usage, this section defines the minimal set of response codes in
common use by servers that a client will need to understand. While
some clients may be constructed with simple tooling that does not
account for all of these response codes, a more robust client
accounting for these codes will likely provide a better user
experience. It is expected that usage of response codes and types
for this application not defined here will be described in subsequent
documents.
<span class="h3"><a class="selflink" id="section-5.1" href="#section-5.1">5.1</a>. Positive Answers</span>
If a server has the information requested by the client and wishes to
respond to the client with the information according to its policies,
it returns that answer in the body of a 200 (OK) response (see
[<a href="./rfc7231" title=""Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content"">RFC7231</a>]).
<span class="h3"><a class="selflink" id="section-5.2" href="#section-5.2">5.2</a>. Redirects</span>
If a server wishes to inform a client that the answer to a given
query can be found elsewhere, it returns either a 301 (Moved
Permanently) response code to indicate a permanent move or a 302
(Found), 303 (See Other), or 307 (Temporary Redirect) response code
to indicate a non-permanent redirection, and it includes an HTTP(S)
URL in the Location header field (see [<a href="./rfc7231" title=""Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content"">RFC7231</a>]). The client is
expected to issue a subsequent request to satisfy the original query
using the given URL without any processing of the URL. In other
words, the server is to hand back a complete URL, and the client
should not have to transform the URL to follow it. Servers are under
no obligation to return a URL conformant to [<a href="./rfc7482" title=""Registration Data Access Protocol (RDAP) Query Format"">RFC7482</a>].
For this application, such an example of a permanent move might be a
Top-Level Domain (TLD) operator informing a client the information
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being sought can be found with another TLD operator (i.e., a query
for the domain bar in foo.example is found at
http://foo.example/domain/bar).
For example, if the client uses
http://serv1.example.com/weirds/domain/example.com
the server redirecting to
https://serv2.example.net/weirds2/
would set the Location: field to the value
https://serv2.example.net/weirds2/domain/example.com
<span class="h3"><a class="selflink" id="section-5.3" href="#section-5.3">5.3</a>. Negative Answers</span>
If a server wishes to respond that it has an empty result set (that
is, no data appropriately satisfying the query), it returns a 404
(Not Found) response code. Optionally, it MAY include additional
information regarding the negative answer in the HTTP entity body.
If a server wishes to inform the client that information about the
query is available, but cannot include the information in the
response to the client for policy reasons, the server MUST respond
with an appropriate response code out of HTTP's 4xx range. A client
MAY retry the query if that is appropriate for the respective
response code.
<span class="h3"><a class="selflink" id="section-5.4" href="#section-5.4">5.4</a>. Malformed Queries</span>
If a server receives a query that it cannot interpret as an RDAP
query, it returns a 400 (Bad Request) response code. Optionally, it
MAY include additional information regarding this negative answer in
the HTTP entity body.
<span class="h3"><a class="selflink" id="section-5.5" href="#section-5.5">5.5</a>. Rate Limits</span>
Some servers apply rate limits to deter address scraping and other
abuses. When a server declines to answer a query due to rate limits,
it returns a 429 (Too Many Requests) response code as described in
[<a href="./rfc6585" title=""Additional HTTP Status Codes"">RFC6585</a>]. A client that receives a 429 response SHOULD decrease its
query rate and honor the Retry-After header field if one is present.
Servers may place stricter limits upon clients that do not honor the
Retry-After header. Optionally, the server MAY include additional
information regarding the rate limiting in the HTTP entity body.
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Note that this is not a defense against denial-of-service (DoS)
attacks, since a malicious client could ignore the code and continue
to send queries at a high rate. A server might use another response
code if it did not wish to reveal to a client that rate limiting is
the reason for the denial of a reply.
<span class="h3"><a class="selflink" id="section-5.6" href="#section-5.6">5.6</a>. Cross-Origin Resource Sharing (CORS)</span>
When responding to queries, it is RECOMMENDED that servers use the
Access-Control-Allow-Origin header field, as specified by
[<a href="#ref-W3C.REC-cors-20140116">W3C.REC-cors-20140116</a>]. A value of "*" is suitable when RDAP is
used for public resources.
This header (often called the CORS header) helps in-browser web
applications by lifting the "same-origin" restriction (i.e., a
browser may load RDAP client code from one web server but query
others for RDAP data).
By default, browsers do not send cookies when cross origin requests
are allowed. Setting the Access-Control-Allow-Credentials header
field to "true" will send cookies. Use of the
Access-Control-Allow-Credentials header field is NOT RECOMMENDED.
<span class="h2"><a class="selflink" id="section-6" href="#section-6">6</a>. Extensibility</span>
For extensibility purposes, this document defines an IANA registry
for prefixes used in JSON [<a href="./rfc7159" title=""The JavaScript Object Notation (JSON) Data Interchange Format"">RFC7159</a>] data serialization and URI path
segments (see <a href="#section-8">Section 8</a>).
Prefixes and identifiers SHOULD only consist of the alphabetic US-
ASCII characters A through Z in both uppercase and lowercase, the
numerical digits 0 through 9, and the underscore character, and they
SHOULD NOT begin with an underscore character, numerical digit, or
the characters "xml". The following describes the production of JSON
names in ABNF [<a href="./rfc5234" title=""Augmented BNF for Syntax Specifications: ABNF"">RFC5234</a>].
name = ALPHA *( ALPHA / DIGIT / "_" )
Figure 1: ABNF for JSON Names
This restriction is a union of the Ruby programming language
identifier syntax and the XML element name syntax and has two
purposes. First, client implementers using modern programming
languages such as Ruby or Java can use libraries that automatically
promote JSON names to first-order object attributes or members.
Second, a clean mapping between JSON and XML is easy to accomplish
using these rules.
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<span class="h2"><a class="selflink" id="section-7" href="#section-7">7</a>. Security Considerations</span>
This document does not pose strong security requirements to the RDAP
protocol. However, it does not restrict against the use of security
mechanisms offered by the HTTP protocol. It does require that RDAP
clients and servers MUST support HTTPS.
This document makes recommendations for server implementations
against DoS (<a href="#section-5.5">Section 5.5</a>) and interoperability with existing security
mechanisms in HTTP clients (<a href="#section-5.6">Section 5.6</a>).
Additional security considerations to the RDAP protocol are covered
in [<a href="./rfc7481" title=""Security Services for the Registration Data Access Protocol (RDAP)"">RFC7481</a>].
<span class="h2"><a class="selflink" id="section-8" href="#section-8">8</a>. IANA Considerations</span>
<span class="h3"><a class="selflink" id="section-8.1" href="#section-8.1">8.1</a>. RDAP Extensions Registry</span>
IANA has created a new category in the protocol registries labeled
"Registration Data Access Protocol (RDAP)", and within that category,
has established a URL-referenceable, stand-alone registry labeled
"RDAP Extensions". The purpose of this registry is to ensure
uniqueness of extension identifiers. The extension identifier is
used as a prefix in JSON names and as a prefix of path segments in
RDAP URLs.
The production rule for these identifiers is specified in <a href="#section-6">Section 6</a>.
In accordance with [<a href="./rfc5226" title="">RFC5226</a>], the IANA policy for assigning new
values, shall be Specification Required: values and their meanings
must be documented in an RFC or in some other permanent and readily
available reference, in sufficient detail that interoperability
between independent implementations is possible.
The following is a template for an RDAP extension registration:
Extension identifier: the identifier of the extension
Registry operator: the name of the registry operator
Published specification: RFC number, bibliographical reference, or
URL to a permanent and readily available specification
Person & email address to contact for further information: The
names and email addresses of individuals to contact regarding this
registry entry
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Intended usage: brief reasons for this registry entry (as defined
by [<a href="./rfc5226" title="">RFC5226</a>]).
The following is an example of a registration in the RDAP extension
registry:
Extension identifier: lunarNic
Registry operator: The Registry of the Moon, LLC
Published specification: http://www.example/moon_apis/rdap
Person & email address to contact for further information:
Professor Bernardo de la Paz <berny@moon.example>
Intended usage: COMMON
<span class="h2"><a class="selflink" id="section-9" href="#section-9">9</a>. Internationalization Considerations</span>
<span class="h3"><a class="selflink" id="section-9.1" href="#section-9.1">9.1</a>. URIs and IRIs</span>
Clients can use Internationalized Resource Identifiers (IRIs)
[<a href="./rfc3987" title=""Internationalized Resource Identifiers (IRIs)"">RFC3987</a>] for internal use as they see fit but MUST transform them to
URIs [<a href="./rfc3986" title=""Uniform Resource Identifier (URI): Generic Syntax"">RFC3986</a>] for interaction with RDAP servers. RDAP servers MUST
use URIs in all responses, and again clients can transform these URIs
to IRIs for internal use as they see fit.
<span class="h3"><a class="selflink" id="section-9.2" href="#section-9.2">9.2</a>. Language Identifiers in Queries and Responses</span>
Under most scenarios, clients requesting data will not signal that
the data be returned in a particular language or script. On the
other hand, when servers return data and have knowledge that the data
is in a language or script, the data SHOULD be annotated with
language identifiers whenever they are available, thus allowing
clients to process and display the data accordingly.
[<a id="ref-RFC7483">RFC7483</a>] provides such a mechanism.
<span class="h3"><a class="selflink" id="section-9.3" href="#section-9.3">9.3</a>. Language Identifiers in HTTP Headers</span>
Given the description of the use of language identifiers in
<a href="#section-9.2">Section 9.2</a>, unless otherwise specified, servers SHOULD ignore the
HTTP [<a href="./rfc7231" title=""Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content"">RFC7231</a>] Accept-Language header field when formulating HTTP
entity responses, so that clients do not conflate the Accept-Language
header with the 'lang' values in the entity body.
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However, servers MAY return language identifiers in the Content-
Language header field so as to inform clients of the intended
language of HTTP layer messages.
<span class="h2"><a class="selflink" id="section-10" href="#section-10">10</a>. References</span>
<span class="h3"><a class="selflink" id="section-10.1" href="#section-10.1">10.1</a>. Normative References</span>
[<a id="ref-RFC2119">RFC2119</a>] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", <a href="https://www.rfc-editor.org/bcp/bcp14">BCP 14</a>, <a href="./rfc2119">RFC 2119</a>, March 1997,
<<a href="https://www.rfc-editor.org/info/rfc2119">http://www.rfc-editor.org/info/rfc2119</a>>.
[<a id="ref-RFC3986">RFC3986</a>] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, <a href="./rfc3986">RFC</a>
<a href="./rfc3986">3986</a>, January 2005,
<<a href="https://www.rfc-editor.org/info/rfc3986">http://www.rfc-editor.org/info/rfc3986</a>>.
[<a id="ref-RFC3987">RFC3987</a>] Duerst, M. and M. Suignard, "Internationalized Resource
Identifiers (IRIs)", <a href="./rfc3987">RFC 3987</a>, January 2005,
<<a href="https://www.rfc-editor.org/info/rfc3987">http://www.rfc-editor.org/info/rfc3987</a>>.
[<a id="ref-RFC5226">RFC5226</a>] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", <a href="https://www.rfc-editor.org/bcp/bcp26">BCP 26</a>, <a href="./rfc5226">RFC 5226</a>,
May 2008, <<a href="https://www.rfc-editor.org/info/rfc5226">http://www.rfc-editor.org/info/rfc5226</a>>.
[<a id="ref-RFC6585">RFC6585</a>] Nottingham, M. and R. Fielding, "Additional HTTP Status
Codes", <a href="./rfc6585">RFC 6585</a>, April 2012,
<<a href="https://www.rfc-editor.org/info/rfc6585">http://www.rfc-editor.org/info/rfc6585</a>>.
[<a id="ref-RFC7230">RFC7230</a>] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing", <a href="./rfc7230">RFC</a>
<a href="./rfc7230">7230</a>, June 2014, <<a href="https://www.rfc-editor.org/info/rfc7230">http://www.rfc-editor.org/info/rfc7230</a>>.
[<a id="ref-RFC7231">RFC7231</a>] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", <a href="./rfc7231">RFC 7231</a>,
June 2014, <<a href="https://www.rfc-editor.org/info/rfc7231">http://www.rfc-editor.org/info/rfc7231</a>>.
[<a id="ref-RFC7481">RFC7481</a>] Hollenbeck, S. and N. Kong, "Security Services for the
Registration Data Access Protocol (RDAP)", <a href="./rfc7481">RFC 7481</a>,
February 2015, <<a href="https://www.rfc-editor.org/info/rfc7481">http://www.rfc-editor.org/info/rfc7481</a>>.
[<a id="ref-RFC7482">RFC7482</a>] Newton, A. and S. Hollenbeck, "Registration Data Access
Protocol (RDAP) Query Format", <a href="./rfc7482">RFC 7482</a>, February 2015,
<<a href="https://www.rfc-editor.org/info/rfc7482">http://www.rfc-editor.org/info/rfc7482</a>>.
[<a id="ref-RFC7483">RFC7483</a>] Newton, A. and S. Hollenbeck, "JSON Responses for the
Registration Data Access Protocol (RDAP)", <a href="./rfc7483">RFC 7483</a>,
February 2015, <<a href="https://www.rfc-editor.org/info/rfc7483">http://www.rfc-editor.org/info/rfc7483</a>>.
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[<a id="ref-RFC7484">RFC7484</a>] Blanchet, M., "Finding the Authoritative Registration Data
(RDAP) Service", <a href="./rfc7484">RFC 7484</a>, February 2015,
<<a href="https://www.rfc-editor.org/info/rfc7484">http://www.rfc-editor.org/info/rfc7484</a>>.
[<a id="ref-W3C.REC-cors-20140116">W3C.REC-cors-20140116</a>]
Kesteren, A., "Cross-Origin Resource Sharing", W3C
Recommendation, REC-cors-20140116, January 2014,
<<a href="http://www.w3.org/TR/2014/REC-cors-20140116/">http://www.w3.org/TR/2014/REC-cors-20140116/</a>>.
<span class="h3"><a class="selflink" id="section-10.2" href="#section-10.2">10.2</a>. Informative References</span>
[<a id="ref-REST">REST</a>] Fielding, R. and R. Taylor, "Principled Design of the
Modern Web Architecture", ACM Transactions on Internet
Technology, Vol. 2, No. 2, May 2002.
[<a id="ref-RFC3912">RFC3912</a>] Daigle, L., "WHOIS Protocol Specification", <a href="./rfc3912">RFC 3912</a>,
September 2004, <<a href="https://www.rfc-editor.org/info/rfc3912">http://www.rfc-editor.org/info/rfc3912</a>>.
[<a id="ref-RFC5234">RFC5234</a>] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, <a href="./rfc5234">RFC 5234</a>, January 2008,
<<a href="https://www.rfc-editor.org/info/rfc5234">http://www.rfc-editor.org/info/rfc5234</a>>.
[<a id="ref-RFC5890">RFC5890</a>] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document Framework",
<a href="./rfc5890">RFC 5890</a>, August 2010,
<<a href="https://www.rfc-editor.org/info/rfc5890">http://www.rfc-editor.org/info/rfc5890</a>>.
[<a id="ref-RFC7159">RFC7159</a>] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", <a href="./rfc7159">RFC 7159</a>, March 2014,
<<a href="https://www.rfc-editor.org/info/rfc7159">http://www.rfc-editor.org/info/rfc7159</a>>.
[<a id="ref-SAC-051">SAC-051</a>] Piscitello, D., Ed., "SSAC Report on Domain Name WHOIS
Terminology and Structure", A report from the ICANN
Security and Stability Advisory Committee (SSAC),
September 2011.
[<a id="ref-lacnic-joint-whois">lacnic-joint-whois</a>]
LACNIC, "Joint Whois", December 2005,
<<a href="ftp://[email protected]/pub/gter/gter20/02-jwhois-lacnic.pdf">ftp://[email protected]/pub/gter/</a>
<a href="ftp://[email protected]/pub/gter/gter20/02-jwhois-lacnic.pdf">gter20/02-jwhois-lacnic.pdf</a>>.
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<span class="h2"><a class="selflink" id="appendix-A" href="#appendix-A">Appendix A</a>. Protocol Example</span>
To demonstrate typical behavior of an RDAP client and server, the
following is an example of an exchange, including a redirect. The
data in the response has been elided for brevity, as the data format
is not described in this document. The media type used here is
described in [<a href="./rfc7483" title=""JSON Responses for the Registration Data Access Protocol (RDAP)"">RFC7483</a>].
An example of an RDAP client and server exchange:
Client:
<TCP connect to rdap.example.com port 80>
GET /rdap/ip/203.0.113.0/24 HTTP/1.1
Host: rdap.example.com
Accept: application/rdap+json
rdap.example.com:
HTTP/1.1 301 Moved Permanently
Location: http://rdap-ip.example.com/rdap/ip/203.0.113.0/24
Content-Length: 0
Content-Type: application/rdap+json
<TCP disconnect>
Client:
<TCP connect to rdap-ip.example.com port 80>
GET /rdap/ip/203.0.113.0/24 HTTP/1.1
Host: rdap-ip.example.com
Accept: application/rdap+json
rdap-ip.example.com:
HTTP/1.1 200 OK
Content-Type: application/rdap+json
Content-Length: 9001
{ ... }
<TCP disconnect>
<span class="h2"><a class="selflink" id="appendix-B" href="#appendix-B">Appendix B</a>. Cache Busting</span>
Some HTTP [<a href="./rfc7230" title=""Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing"">RFC7230</a>] cache infrastructures do not adhere to caching
standards adequately and could cache responses longer than is
intended by the server. To overcome these issues, clients can use an
ad hoc and improbably used query parameter with a random value of
their choosing. As <a href="#section-4.3">Section 4.3</a> instructs servers to ignore unknown
parameters, this is compatible with the RDAP definition.
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An example of using an unknown query parameter to bust caches:
http://example.com/ip/192.0.2.0?__fuhgetaboutit=xyz123
Use of an unknown parameter to overcome misbehaving caches is not
part of any specification and is offered here for informational
purposes.
<span class="h2"><a class="selflink" id="appendix-C" href="#appendix-C">Appendix C</a>. Bootstrapping and Redirection</span>
The traditional deployment model of WHOIS [<a href="./rfc3912" title=""WHOIS Protocol Specification"">RFC3912</a>] does not provide
a mechanism for determining the authoritative source for information.
Some approaches have been implemented in the past, most notably the
Joint WHOIS [<a href="#ref-lacnic-joint-whois">lacnic-joint-whois</a>] initiative. However, among other
shortcomings, Joint WHOIS is implemented using proxies and server-
side referrals.
These issues are solved in RDAP using HTTP redirects and
bootstrapping. Bootstrapping is discussed in [<a href="./rfc7484" title=""Finding the Authoritative Registration Data (RDAP) Service"">RFC7484</a>]. In
constrained environments, the processes outlined in [<a href="./rfc7484" title=""Finding the Authoritative Registration Data (RDAP) Service"">RFC7484</a>] may not
be viable, and there may be the need for servers acting as a
"redirector".
Redirector servers issue HTTP redirects to clients using a
redirection table informed by [<a href="./rfc7484" title=""Finding the Authoritative Registration Data (RDAP) Service"">RFC7484</a>]. Figure 2 diagrams a client
using a redirector for bootstrapping.
REDIRECTOR ARIN
RDAP RDAP
. .
| |
Q: 23.1.1.1? -----------------> | |
| |
<---------- HTTP 301 --------| |
('Try ARIN RDAP') | |
| |
|
Q: 23.1.1.1? -------------------------------> |
|
<---------- HTTP 200 --------------------- |
(JSON response is returned) |
|
|
.
Figure 2: Querying RDAP Data for 23.1.1.1
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In some cases, particularly sub-delegations made between Regional
Internet Registries (RIRs) known as "ERX space" and transfers of
networks, multiple HTTP redirects will be issued. Figure 3 shows
such a scenario.
REDIRECTOR LACNIC ARIN
RDAP RDAP RDAP
. . .
Q: 23.1.1.1? ----> | | |
| | |
<-- HTTP 301 --- | | |
('Try LACNIC') | | |
| | |
| | |
Q: 23.1.1.1? -----------------> | |
| |
<---------- HTTP 301 --------| |
('Try ARIN RDAP') | |
| |
|
Q: 23.1.1.1? -------------------------------> |
|
<---------- HTTP 200 --------------------- |
(JSON response is returned) |
|
|
.
Figure 3: Querying RDAP Data for Data That Has Been Transferred
Acknowledgements
John Levine provided text to tighten up the Accept header field usage
and the text for the section on 429 responses.
Marc Blanchet provided some clarifying text regarding the use of URLs
with redirects, as well as very useful feedback during Working Group
Last Call (WGLC).
Normative language reviews were provided by Murray S. Kucherawy,
Andrew Sullivan, Tom Harrison, Ed Lewis, and Alexander Mayrhofer.
Jean-Phillipe Dionne provided text for the Security Considerations
section.
The concept of the redirector server informatively discussed in
<a href="#appendix-C">Appendix C</a> was documented by Carlos M. Martinez and Gerardo Rada of
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LACNIC and Linlin Zhou of CNNIC and subsequently incorporated into
this document.
This document is the work product of the IETF's WEIRDS working group,
of which Olaf Kolkman and Murray Kucherawy were chairs.
Authors' Addresses
Andrew Lee Newton
American Registry for Internet Numbers
3635 Concorde Parkway
Chantilly, VA 20151
United States
EMail: [email protected]
URI: <a href="http://www.arin.net">http://www.arin.net</a>
Byron J. Ellacott
Asia Pacific Network Information Centre
6 Cordelia Street
South Brisbane QLD 4101
Australia
EMail: [email protected]
URI: <a href="http://www.apnic.net">http://www.apnic.net</a>
Ning Kong
China Internet Network Information Center
4 South 4th Street, Zhongguancun, Haidian District
Beijing 100190
China
Phone: +86 10 5881 3147
EMail: [email protected]
Newton, et al. Standards Track [Page 16]
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