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Versions: (draft-designteam-weirds-using-http) 00 01 03 04 05 06 07 08 09 10 11 12 13 14 15 RFC 7480

Network Working Group                                          A. Newton
Internet-Draft                                                      ARIN
Intended status: Standards Track                             B. Ellacott
Expires: April 10, 2015                                            APNIC
                                                                 N. Kong
                                                                   CNNIC
                                                         October 7, 2014


       HTTP usage in the Registration Data Access Protocol (RDAP)
                    draft-ietf-weirds-using-http-13

Abstract

   This document is one of a collection that together describe 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 Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 10, 2015.

Copyright Notice

   Copyright (c) 2014 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
   (http://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



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   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Design Intents  . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Queries . . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     4.1.  HTTP Methods  . . . . . . . . . . . . . . . . . . . . . .   5
     4.2.  Accept Header . . . . . . . . . . . . . . . . . . . . . .   5
     4.3.  Query Parameters  . . . . . . . . . . . . . . . . . . . .   5
   5.  Types of HTTP Response  . . . . . . . . . . . . . . . . . . .   6
     5.1.  Positive Answers  . . . . . . . . . . . . . . . . . . . .   6
     5.2.  Redirects . . . . . . . . . . . . . . . . . . . . . . . .   6
     5.3.  Negative Answers  . . . . . . . . . . . . . . . . . . . .   7
     5.4.  Malformed Queries . . . . . . . . . . . . . . . . . . . .   7
     5.5.  Rate Limits . . . . . . . . . . . . . . . . . . . . . . .   7
     5.6.  Cross-Origin Resource Sharing . . . . . . . . . . . . . .   7
   6.  Extensibility . . . . . . . . . . . . . . . . . . . . . . . .   8
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
     8.1.  RDAP Extensions Registry  . . . . . . . . . . . . . . . .   9
   9.  Internationalization Considerations . . . . . . . . . . . . .  10
     9.1.  URIs and IRIs . . . . . . . . . . . . . . . . . . . . . .  10
     9.2.  Language Identifiers in Queries and Responses . . . . . .  10
     9.3.  Language Identifiers in HTTP Headers  . . . . . . . . . .  10
   10. Contributing Authors and Acknowledgements . . . . . . . . . .  10
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  11
     11.2.  Informative References . . . . . . . . . . . . . . . . .  12
   Appendix A.  Protocol Example . . . . . . . . . . . . . . . . . .  12
   Appendix B.  Cache Busting  . . . . . . . . . . . . . . . . . . .  13
   Appendix C.  Bootstrapping and Redirection  . . . . . . . . . . .  14
   Appendix D.  Changelog  . . . . . . . . . . . . . . . . . . . . .  15
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  19

1.  Introduction

   This document describes the usage of the Hypertext Transfer Protocol
   (HTTP) [RFC7230] for registration data directory services.  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 [REST] architectural style.  By
   giving the various directory services common behavior, a single



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   client is better able to retrieve data from directory services
   adhering to this behavior.

   The registration data expected to be presented by this service is
   Internet resource registration data - registration of domain names
   and Internet number resources.  These data is typically provided by
   WHOIS [RFC3912] 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, [RFC5890]), and support for localized
   registration data such as addresses and organisation 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 URL to use in such queries.
       [I-D.ietf-weirds-bootstrap] describes one method to determine the
       server and the base URL.  See Appendix C for more information.

   2.  A client issues an HTTP (or HTTPS) query using GET [RFC7231].  As
       an example, a query for the network registration 192.0.2.0 might
       be

          http://example.com/rdap/ip/192.0.2.0

       [I-D.ietf-weirds-rdap-query] details the various queries used in
       RDAP.

   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.  [I-D.ietf-weirds-json-response] 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 (Uniform
       Resource Locator) pointing to the information or another server



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       known to have knowledge of the location of the information.  The
       client is expected to re-query 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.

2.  Terminology

   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 RFC 2119 [RFC2119].

   As is noted in Security and Stability Advisory Committee (SSAC)
   Report on WHOIS Terminology and Structure [SAC-051], the term "WHOIS"
   is overloaded, often referring to a protocol, a service and data.  In
   accordance with [SAC-051], this document describes the base behavior
   for a Registration Data Access Protocol (RDAP).  [SAC-051] 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
   [I-D.ietf-weirds-rdap-query] and [I-D.ietf-weirds-json-response],
   while this document describes how RDAP clients and servers use HTTP
   to exchange queries and responses.  [I-D.ietf-weirds-rdap-sec]
   describes security considerations for RDAP.

3.  Design Intents

   There are a few design criteria this document attempts to meet.

   First, each query is meant to return 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 satisfy a query.

   Second, the semantics of the request/response allow for future and/or
   non-standard response formats.  In this document, only a JSON



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   [RFC7159] response media type is noted, with the response contents to
   be described separately (see [I-D.ietf-weirds-json-response]).  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, and widespread programmer understanding
   of client behaviours for web services styled after REST [REST],
   reducing the cost to deploy Registration Data Directory Services and
   clients.

4.  Queries

4.1.  HTTP Methods

   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 [RFC7231]).
   Servers are under no obligation to support other HTTP methods,
   therefore clients using other methods will likely not interoperate
   properly.

   Clients MUST support HTTPS as well as HTTP.

4.2.  Accept Header

   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.

   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.

4.3.  Query Parameters

   Servers MUST ignore unknown query parameters.  Use of unknown query
   parameters for cache-busting is described in Appendix B.





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5.  Types of HTTP Response

   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.

5.1.  Positive Answers

   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 response.

5.2.  Redirects

   If a server wishes to inform a client that the answer to a given
   query can be found elsewhere, it returns either a 301 response code
   to indicate a permanent move, or a 302, 303 or 307 response code to
   indicate a non-permanent redirection, and it includes an HTTP(s) URL
   in the Location: header field.  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 [I-D.ietf-weirds-rdap-query].

   For this application, such an example of a permanent move might be a
   Top Level Domain (TLD) operator informing a client the information
   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 sends

      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




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      https://serv2.example.net/weirds2/domain/example.com

5.3.  Negative Answers

   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
   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.  Clients
   MAY retry the query based on the respective response code.

5.4.  Malformed Queries

   If a server receives a query which it cannot interpret as an RDAP
   query, it returns a 400 response code.  Optionally, it MAY include
   additional information regarding this negative answer in the HTTP
   entity body.

5.5.  Rate Limits

   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 response code as described in [RFC6585].  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.

   Note that this is not a defense against denial-of-service 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.

5.6.  Cross-Origin Resource Sharing

   When responding to queries, it is RECOMMENDED that servers use the
   Access-Control-Allow-Origin header field, as specified by
   [W3C.CR-cors-20130129].  As the use of RDAP is for public resources,
   a value of "*" is suitable for most cases.

   This header (often called the CORS header) helps in-browser web
   applications by lifting the "same-origin" restriction.




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6.  Extensibility

   For extensibility purposes, this document defines an IANA registry
   for prefixes used in JSON [RFC7159] data serialization and URI path
   segments (see Section 8).

   Prefixes and identifiers SHOULD only consist of the alphabetic ASCII
   characters A through Z in both uppercase and lowercase, the numerical
   digits 0 through 9, underscore characters, and SHOULD NOT begin with
   an underscore character, numerical digit or the characters "xml".
   The following describes the production of JSON names in ABNF
   [RFC5234].

   ABNF for JSON names


     name = ALPHA *( ALPHA / DIGIT / "_" )


                                 Figure 1

   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.

7.  Security Considerations

   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 the RDAP
   clients MUST support HTTPS.

   This document made recommendations for server implementations against
   denial-of-service (Section 5.5) and interoperability with existing
   security mechanism in HTTP clients (Section 5.6).

   Additional security considerations to the RDAP protocol are covered
   in [I-D.ietf-weirds-rdap-sec].

8.  IANA Considerations







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8.1.  RDAP Extensions Registry

   This specification proposes an IANA registry for 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 Section 6.

   In accordance with [RFC5226], 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 preliminary 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 for contact regarding
      this registry entry

      Intended usage: brief reasons for this registry entry (as defined
      by [RFC5226].

   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






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9.  Internationalization Considerations

9.1.  URIs and IRIs

   Clients can use IRIs [RFC3987] for internal use as they see fit, but
   MUST transform them to URIs [RFC3986] 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.

9.2.  Language Identifiers in Queries and Responses

   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.

   [I-D.ietf-weirds-json-response] provides such a mechanism.

9.3.  Language Identifiers in HTTP Headers

   Given the description of the use of language identifiers in
   Section 9.2, unless otherwise specified, servers SHOULD ignore the
   HTTP [RFC7231] 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.

   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.

10.  Contributing Authors and 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 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.





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   The concept of the redirector server informatively discussed in
   Appendix C was documented by Carlos M.  Martinez and Gerardo Rada of
   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.

11.  References

11.1.  Normative References

   [I-D.ietf-weirds-bootstrap]
              Blanchet, M. and G. Leclanche, "Finding the Authoritative
              Registration Data (RDAP) Service", draft-ietf-weirds-
              bootstrap-07 (work in progress), September 2014.

   [I-D.ietf-weirds-json-response]
              Newton, A. and S. Hollenbeck, "JSON Responses for the
              Registration Data Access Protocol (RDAP)", draft-ietf-
              weirds-json-response-09 (work in progress), September
              2014.

   [I-D.ietf-weirds-rdap-query]
              Newton, A. and S. Hollenbeck, "Registration Data Access
              Protocol Query Format", draft-ietf-weirds-rdap-query-14
              (work in progress), September 2014.

   [I-D.ietf-weirds-rdap-sec]
              Hollenbeck, S. and N. Kong, "Security Services for the
              Registration Data Access Protocol", draft-ietf-weirds-
              rdap-sec-09 (work in progress), September 2014.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66, RFC
              3986, January 2005.

   [RFC3987]  Duerst, M. and M. Suignard, "Internationalized Resource
              Identifiers (IRIs)", RFC 3987, January 2005.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.





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   [RFC6585]  Nottingham, M. and R. Fielding, "Additional HTTP Status
              Codes", RFC 6585, April 2012.

   [RFC7230]  Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
              (HTTP/1.1): Message Syntax and Routing", RFC 7230, June
              2014.

   [RFC7231]  Fielding, R. and J. Reschke, "Hypertext Transfer Protocol
              (HTTP/1.1): Semantics and Content", RFC 7231, June 2014.

   [W3C.CR-cors-20130129]
              Kesteren, A., "Cross-Origin Resource Sharing", World Wide
              Web Consortium Candidate Recommendation CR-cors-20130129,
              January 2013,
              <http://www.w3.org/TR/2013/CR-cors-20130129>.

11.2.  Informative References

   [REST]     Fielding, R. and R. Taylor, "Principled Design of the
              Modern Web Architecture", ACM Transactions on Internet
              Technology Vol. 2, No. 2, May 2002.

   [RFC3912]  Daigle, L., "WHOIS Protocol Specification", RFC 3912,
              September 2004.

   [RFC5234]  Crocker, D. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234, January 2008.

   [RFC5890]  Klensin, J., "Internationalized Domain Names for
              Applications (IDNA): Definitions and Document Framework",
              RFC 5890, August 2010.

   [RFC7159]  Bray, T., "The JavaScript Object Notation (JSON) Data
              Interchange Format", RFC 7159, March 2014.

   [SAC-051]  Piscitello, D., Ed., "SSAC Report on Domain Name WHOIS
              Terminology and Structure", September 2011.

   [lacnic-joint-whois]
              LACNIC, "LACNIC Joint WHOIS Implementation", 2005,
              <ftp://anonymous@ftp.registro.br/pub/gter/gter20/02-
              jwhois-lacnic.pdf>.

Appendix A.  Protocol Example

   To demonstrate typical behaviour 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



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   is not described in this document.  The media type used here is
   described in [I-D.ietf-weirds-json-response].

   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>


Appendix B.  Cache Busting

   Some HTTP [RFC7230] cache infrastructure does 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
   adhoc and improbably used query parameter with a random value of
   their choosing.  As Section 4.3 instructs servers to ignore unknown
   parameters, this is unlikely to have any known side effects.

   An example of using an unknown query parameter to bust caches:


     http://example.com/ip/192.0.2.0?__fuhgetaboutit=xyz123




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   Use of an unknown parameter to overcome misbehaving caches is not
   part of any specification and is offered here for informational
   purposes.

Appendix C.  Bootstrapping and Redirection

   The traditional deployment model of WHOIS [RFC3912] 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 [lacnic-joint-whois] 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
   [I-D.ietf-weirds-bootstrap].  In constrained environments, the
   processes outlined in [I-D.ietf-weirds-bootstrap] may not be viable
   and there may be need for servers acting as a "redirector".

   Redirector servers issue HTTP redirects to clients using a
   redirection table informed by [I-D.ietf-weirds-bootstrap].  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)         |
                                                        |
                                                        |
                                                        .

                      Querying RDAP data for 23.1.1.1

                                 Figure 2






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   In some cases, particularly sub-delegations made between 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)         |
                                                        |
                                                        |
                                                        .

           Querying RDAP data for data that has been transfered

                                 Figure 3

Appendix D.  Changelog

   RFC Editor: Please remove this section.

   Initial WG -00:  Updated to working group document 2012-September-20

   -01

      *  Updated for the sections moved to the JSON responses draft.

      *  Simplified media type, removed "level" parameter.

      *  Updated 2119 language and added boilerplate.

      *  In section 1, noted that redirects can go to redirect servers
         as well.




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      *  Added Section 9.2 and Section 9.3.

   -02

      *  Added a section on 429 response codes.

      *  Changed Accept header language in section 4.1

      *  Removed reference to the now dead requirements draft.

      *  Added contributing authors and acknowledgements section.

      *  Added some clarifying text regarding complete URLs in the
         redirect section.

      *  Changed media type to application/rdap+json

      *  Added media type registration

   -03

      *  Removed forward reference to draft-ietf-weirds-json-response.

      *  Added reference and recommended usage of CORS

   -04

      *  Revised introduction and abstract.

      *  Added negative responses other than 404.

      *  Added security considerations.

      *  Added and corrected references: CORS, RFC3912, RFC3987,
         RFC5890.

      *  Expanded on first use several acronyms.

      *  Updated 2119 language.

   -05

      *  Update the media type registration.

      *  Further explained the SHOULD in section 5.

      *  Split the references into normative and informative.




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      *  Other minor fixes.

   -06

      *  Rewritten the third paragraph in Section 3 to avoid
         contradictions

      *  Simplified the wording in Seciton 5.1.

      *  Removed some RFC 2119 words in Section 5.2, 5.3, 5.4 and 5.5.

      *  Corrected RFC 6839 as an informative reference.

      *  Replaced MAYs with cans in Seciton 9.1.

      *  Replaced MAY with can in Appendix B.

      *  Added a note in in Appendix C for the RFC Editor to remove this
         section.

   -07

      *  Dropped reference to MUST with application/rdap+json

      *  Dropped IANA registration of application/rdap+json

   -08

      *  Keep alive version.

   -09

      *  Changed status lines in example to include http version number.

      *  Removed charset from media types in examples.

      *  Changed wording of 404 negative response to specifically say
         "empty result set".

      *  Changed references to HTTP.

   -10

      *  Corrected references to HTTP.

      *  Added a reference to draft-ietf-weirds-json-response (discuss
         item from Barry Leiba)




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      *  Added a reference to draft-ietf-weirds-rdap-query (discuss item
         from Barry Leiba)

      *  Noted that redirect URLs do not have to conform to draft-ietf-
         weirds-rdap-query (comment by Richard Barnes)

      *  Noted that CORS header is most likely to be "*" (comment by
         Richard Barnes)

      *  Added reference to draft-ietf-weirds-rdap-sec (comment by
         Richard Barnes)

      *  Added a sentence to the abstract explaining the purpose of RDAP
         (comment by Stephen Farrell)

      *  Added further references to draft-ietf-weirds-rdap-query and
         draft-ietf-weirds-json-response (comment by Stephen Farrell)

      *  Added comment regarding the use of the CORS header (comment by
         Stephen Farrell)

      *  Explanded SSAC (comment by Sean Turner)

      *  Added text about HEAD and GET.

   -11

      *  Changed JSON reference to RFC 7159.

      *  Noted that clients MUST support HTTPS.

   -12

      *  Added reference to REST.

      *  Numerous textual clarifications.

      *  Added an actual reference to RFC 5226 instead of just talking
         about it.

      *  A reference to draft-ietf-weirds-bootstrap was added.

      *  Included a section on redirectors.

   -13

      *  Addressed AD feedback.




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Authors' Addresses

   Andrew Lee Newton
   American Registry for Internet Numbers
   3635 Concorde Parkway
   Chantilly, VA  20151
   US

   Email: andy@arin.net
   URI:   http://www.arin.net


   Byron J. Ellacott
   Asia Pacific Network Information Center
   6 Cordelia Street
   South Brisbane  QLD 4101
   Australia

   Email: bje@apnic.net
   URI:   http://www.apnic.net


   Ning Kong
   China Internet Network Information Center
   4 South 4th Street, Zhongguancun, Haidian District
   Beijing  100190
   China

   Phone: +86 10 5881 3147
   Email: nkong@cnnic.cn





















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