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6
7Internet Engineering Task Force (IETF) A. Newton
8Request for Comments: 7480 ARIN
9Category: Standards Track B. Ellacott
10ISSN: 2070-1721 APNIC
11 N. Kong
12 CNNIC
13 March 2015
14
15
16 HTTP Usage in the Registration Data Access Protocol (RDAP)
17
18Abstract
19
20 This document is one of a collection that together describes the
21 Registration Data Access Protocol (RDAP). It describes how RDAP is
22 transported using the Hypertext Transfer Protocol (HTTP). RDAP is a
23 successor protocol to the very old WHOIS protocol. The purpose of
24 this document is to clarify the use of standard HTTP mechanisms for
25 this application.
26
27Status of This Memo
28
29 This is an Internet Standards Track document.
30
31 This document is a product of the Internet Engineering Task Force
32 (IETF). It represents the consensus of the IETF community. It has
33 received public review and has been approved for publication by the
34 Internet Engineering Steering Group (IESG). Further information on
35 Internet Standards is available in Section 2 of RFC 5741.
36
37 Information about the current status of this document, any errata,
38 and how to provide feedback on it may be obtained at
39 http://www.rfc-editor.org/info/rfc7480.
40
41Copyright Notice
42
43 Copyright (c) 2015 IETF Trust and the persons identified as the
44 document authors. All rights reserved.
45
46 This document is subject to BCP 78 and the IETF Trust's Legal
47 Provisions Relating to IETF Documents
48 (http://trustee.ietf.org/license-info) in effect on the date of
49 publication of this document. Please review these documents
50 carefully, as they describe your rights and restrictions with respect
51 to this document. Code Components extracted from this document must
52 include Simplified BSD License text as described in Section 4.e of
53 the Trust Legal Provisions and are provided without warranty as
54 described in the Simplified BSD License.
55
56
57
58Newton, et al. Standards Track [Page 1]
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60RFC 7480 RDAP over HTTP March 2015
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62
63Table of Contents
64
65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
66 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
67 3. Design Intents . . . . . . . . . . . . . . . . . . . . . . . 5
68 4. Queries . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
69 4.1. HTTP Methods . . . . . . . . . . . . . . . . . . . . . . 5
70 4.2. Accept Header . . . . . . . . . . . . . . . . . . . . . . 5
71 4.3. Query Parameters . . . . . . . . . . . . . . . . . . . . 6
72 5. Types of HTTP Response . . . . . . . . . . . . . . . . . . . 6
73 5.1. Positive Answers . . . . . . . . . . . . . . . . . . . . 6
74 5.2. Redirects . . . . . . . . . . . . . . . . . . . . . . . . 6
75 5.3. Negative Answers . . . . . . . . . . . . . . . . . . . . 7
76 5.4. Malformed Queries . . . . . . . . . . . . . . . . . . . . 7
77 5.5. Rate Limits . . . . . . . . . . . . . . . . . . . . . . . 7
78 5.6. Cross-Origin Resource Sharing (CORS) . . . . . . . . . . 8
79 6. Extensibility . . . . . . . . . . . . . . . . . . . . . . . . 8
80 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
81 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
82 8.1. RDAP Extensions Registry . . . . . . . . . . . . . . . . 9
83 9. Internationalization Considerations . . . . . . . . . . . . . 10
84 9.1. URIs and IRIs . . . . . . . . . . . . . . . . . . . . . . 10
85 9.2. Language Identifiers in Queries and Responses . . . . . . 10
86 9.3. Language Identifiers in HTTP Headers . . . . . . . . . . 10
87 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
88 10.1. Normative References . . . . . . . . . . . . . . . . . . 11
89 10.2. Informative References . . . . . . . . . . . . . . . . . 12
90 Appendix A. Protocol Example . . . . . . . . . . . . . . . . . . 13
91 Appendix B. Cache Busting . . . . . . . . . . . . . . . . . . . 13
92 Appendix C. Bootstrapping and Redirection . . . . . . . . . . . 14
93 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . 15
94 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
95
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118
1191. Introduction
120
121 This document describes the usage of the Hypertext Transfer Protocol
122 (HTTP) [RFC7230] for the Registration Data Access Protocol (RDAP).
123 The goal of this document is to tie together usage patterns of HTTP
124 into a common profile applicable to the various types of directory
125 services serving registration data using practices informed by the
126 Representational State Transfer (REST) [REST] architectural style.
127 By giving the various directory services common behavior, a single
128 client is better able to retrieve data from directory services
129 adhering to this behavior.
130
131 Registration data expected to be presented by this service is
132 Internet resource registration data -- registration of domain names
133 and Internet number resources. This data is typically provided by
134 WHOIS [RFC3912] services, but the WHOIS protocol is insufficient to
135 modern registration data service requirements. A replacement
136 protocol is expected to retain the simple transactional nature of
137 WHOIS, while providing a specification for queries and responses,
138 redirection to authoritative sources, support for Internationalized
139 Domain Names (IDNs) [RFC5890], and support for localized registration
140 data such as addresses and organization or person names.
141
142 In designing these common usage patterns, this document introduces
143 considerations for a simple use of HTTP. Where complexity may
144 reside, it is the goal of this document to place it upon the server
145 and to keep the client as simple as possible. A client
146 implementation should be possible using common operating system
147 scripting tools (e.g., bash and wget).
148
149 This is the basic usage pattern for this protocol:
150
151 1. A client determines an appropriate server to query along with the
152 appropriate base Uniform Resource Locator (URL) to use in such
153 queries. [RFC7484] describes one method to determine the server
154 and the base URL. See Appendix C for more information.
155
156 2. A client issues an HTTP (or HTTPS) query using GET [RFC7231]. As
157 an example, a query URL for the network registration 192.0.2.0
158 might be
159
160 http://example.com/rdap/ip/192.0.2.0
161
162 [RFC7482] details the various queries used in RDAP.
163
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174
175 3. If the receiving server has the information for the query, it
176 examines the Accept header field of the query and returns a 200
177 response with a response entity appropriate for the requested
178 format. [RFC7483] details a response in JavaScript Object
179 Notation (JSON).
180
181 4. If the receiving server does not have the information for the
182 query but does have knowledge of where the information can be
183 found, it will return a redirection response (3xx) with the
184 Location header field containing an HTTP(S) URL pointing to the
185 information or another server known to have knowledge of the
186 location of the information. The client is expected to requery
187 using that HTTP URL.
188
189 5. If the receiving server does not have the information being 7480:359 ../rdap/rdap.go:148
190 requested and does not have knowledge of where the information
191 can be found, it returns a 404 response.
192
193 6. If the receiving server will not answer a request for policy
194 reasons, it will return an error response (4xx) indicating the
195 reason for giving no answer.
196
197 It is not the intent of this document to redefine the meaning and
198 semantics of HTTP. The purpose of this document is to clarify the
199 use of standard HTTP mechanisms for this application.
200
2012. Terminology
202
203 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
204 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
205 document are to be interpreted as described in [RFC2119].
206
207 As is noted in "Security and Stability Advisory Committee (SSAC)
208 Report on WHOIS Terminology and Structure" [SAC-051], the term
209 "WHOIS" is overloaded, often referring to a protocol, a service, and
210 data. In accordance with [SAC-051], this document describes the base
211 behavior for an RDAP. [SAC-051] describes a protocol profile of RDAP
212 for Domain Name Registries (DNRs), the Domain Name Registration Data
213 Access Protocol (DNRD-AP).
214
215 In this document, an RDAP client is an HTTP user agent performing an
216 RDAP query, and an RDAP server is an HTTP server providing an RDAP
217 response. RDAP query and response formats are described in [RFC7482]
218 and [RFC7483], while this document describes how RDAP clients and
219 servers use HTTP to exchange queries and responses. [RFC7481]
220 describes security considerations for RDAP.
221
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2313. Design Intents
232
233 There are a few design criteria this document attempts to meet.
234
235 First, each query is meant to require only one path of execution to
236 obtain an answer. A response may contain an answer, no answer, or a
237 redirect, and clients are not expected to fork multiple paths of
238 execution to make a query.
239
240 Second, the semantics of the request/response allow for future and/or
241 non-standard response formats. In this document, only a JSON
242 [RFC7159] response media type is noted, with the response contents to
243 be described separately (see [RFC7483]). This document only
244 describes how RDAP is transported using HTTP with this format.
245
246 Third, this protocol is intended to be able to make use of the range
247 of mechanisms available for use with HTTP. HTTP offers a number of
248 mechanisms not described further in this document. Operators are
249 able to make use of these mechanisms according to their local policy,
250 including cache control, authorization, compression, and redirection.
251 HTTP also benefits from widespread investment in scalability,
252 reliability, and performance, as well as widespread programmer
253 understanding of client behaviors for web services styled after REST
254 [REST], reducing the cost to deploy Registration Data Directory
255 Services and clients. This protocol is forward compatible with HTTP
256 2.0.
257
2584. Queries
259
2604.1. HTTP Methods
261
262 Clients use the GET method to retrieve a response body and use the
263 HEAD method to determine existence of data on the server. Clients
264 SHOULD use either the HTTP GET or HEAD methods (see [RFC7231]).
265 Servers are under no obligation to support other HTTP methods;
266 therefore, clients using other methods will likely not interoperate
267 properly.
268
269 Clients and servers MUST support HTTPS to support security services.
270
2714.2. Accept Header
272
273 To indicate to servers that an RDAP response is desired, clients 9083:2372 ../rdap/rdap.go:137
274 include an Accept header field with an RDAP-specific JSON media type,
275 the generic JSON media type, or both. Servers receiving an RDAP
276 request return an entity with a Content-Type header containing the
277 RDAP-specific JSON media type.
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287 This specification does not define the responses a server returns to
288 a request with any other media types in the Accept header field, or
289 with no Accept header field. One possibility would be to return a
290 response in a media type suitable for rendering in a web browser.
291
2924.3. Query Parameters
293
294 Servers MUST ignore unknown query parameters. Use of unknown query
295 parameters for cache busting is described in Appendix B.
296
2975. Types of HTTP Response
298
299 This section describes the various types of responses a server may
300 send to a client. While no standard HTTP response code is forbidden
301 in usage, this section defines the minimal set of response codes in
302 common use by servers that a client will need to understand. While
303 some clients may be constructed with simple tooling that does not
304 account for all of these response codes, a more robust client
305 accounting for these codes will likely provide a better user
306 experience. It is expected that usage of response codes and types
307 for this application not defined here will be described in subsequent
308 documents.
309
3105.1. Positive Answers
311
312 If a server has the information requested by the client and wishes to
313 respond to the client with the information according to its policies,
314 it returns that answer in the body of a 200 (OK) response (see
315 [RFC7231]).
316
3175.2. Redirects
318
319 If a server wishes to inform a client that the answer to a given ../rdap/rdap.go:139
320 query can be found elsewhere, it returns either a 301 (Moved
321 Permanently) response code to indicate a permanent move or a 302
322 (Found), 303 (See Other), or 307 (Temporary Redirect) response code
323 to indicate a non-permanent redirection, and it includes an HTTP(S)
324 URL in the Location header field (see [RFC7231]). The client is
325 expected to issue a subsequent request to satisfy the original query
326 using the given URL without any processing of the URL. In other
327 words, the server is to hand back a complete URL, and the client
328 should not have to transform the URL to follow it. Servers are under
329 no obligation to return a URL conformant to [RFC7482].
330
331 For this application, such an example of a permanent move might be a
332 Top-Level Domain (TLD) operator informing a client the information
333
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343 being sought can be found with another TLD operator (i.e., a query
344 for the domain bar in foo.example is found at
345 http://foo.example/domain/bar).
346
347 For example, if the client uses
348
349 http://serv1.example.com/weirds/domain/example.com
350
351 the server redirecting to
352
353 https://serv2.example.net/weirds2/
354
355 would set the Location: field to the value
356
357 https://serv2.example.net/weirds2/domain/example.com
358
3595.3. Negative Answers 7480:189 ../rdap/rdap.go:148
360
361 If a server wishes to respond that it has an empty result set (that
362 is, no data appropriately satisfying the query), it returns a 404
363 (Not Found) response code. Optionally, it MAY include additional
364 information regarding the negative answer in the HTTP entity body.
365
366 If a server wishes to inform the client that information about the
367 query is available, but cannot include the information in the
368 response to the client for policy reasons, the server MUST respond
369 with an appropriate response code out of HTTP's 4xx range. A client
370 MAY retry the query if that is appropriate for the respective
371 response code.
372
3735.4. Malformed Queries
374
375 If a server receives a query that it cannot interpret as an RDAP
376 query, it returns a 400 (Bad Request) response code. Optionally, it
377 MAY include additional information regarding this negative answer in
378 the HTTP entity body.
379
3805.5. Rate Limits
381
382 Some servers apply rate limits to deter address scraping and other
383 abuses. When a server declines to answer a query due to rate limits,
384 it returns a 429 (Too Many Requests) response code as described in
385 [RFC6585]. A client that receives a 429 response SHOULD decrease its
386 query rate and honor the Retry-After header field if one is present.
387 Servers may place stricter limits upon clients that do not honor the
388 Retry-After header. Optionally, the server MAY include additional
389 information regarding the rate limiting in the HTTP entity body.
390
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399 Note that this is not a defense against denial-of-service (DoS)
400 attacks, since a malicious client could ignore the code and continue
401 to send queries at a high rate. A server might use another response
402 code if it did not wish to reveal to a client that rate limiting is
403 the reason for the denial of a reply.
404
4055.6. Cross-Origin Resource Sharing (CORS)
406
407 When responding to queries, it is RECOMMENDED that servers use the
408 Access-Control-Allow-Origin header field, as specified by
409 [W3C.REC-cors-20140116]. A value of "*" is suitable when RDAP is
410 used for public resources.
411
412 This header (often called the CORS header) helps in-browser web
413 applications by lifting the "same-origin" restriction (i.e., a
414 browser may load RDAP client code from one web server but query
415 others for RDAP data).
416
417 By default, browsers do not send cookies when cross origin requests
418 are allowed. Setting the Access-Control-Allow-Credentials header
419 field to "true" will send cookies. Use of the
420 Access-Control-Allow-Credentials header field is NOT RECOMMENDED.
421
4226. Extensibility
423
424 For extensibility purposes, this document defines an IANA registry
425 for prefixes used in JSON [RFC7159] data serialization and URI path
426 segments (see Section 8).
427
428 Prefixes and identifiers SHOULD only consist of the alphabetic US-
429 ASCII characters A through Z in both uppercase and lowercase, the
430 numerical digits 0 through 9, and the underscore character, and they
431 SHOULD NOT begin with an underscore character, numerical digit, or
432 the characters "xml". The following describes the production of JSON
433 names in ABNF [RFC5234].
434
435 name = ALPHA *( ALPHA / DIGIT / "_" )
436
437 Figure 1: ABNF for JSON Names
438
439 This restriction is a union of the Ruby programming language
440 identifier syntax and the XML element name syntax and has two
441 purposes. First, client implementers using modern programming
442 languages such as Ruby or Java can use libraries that automatically
443 promote JSON names to first-order object attributes or members.
444 Second, a clean mapping between JSON and XML is easy to accomplish
445 using these rules.
446
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454
4557. Security Considerations
456
457 This document does not pose strong security requirements to the RDAP
458 protocol. However, it does not restrict against the use of security
459 mechanisms offered by the HTTP protocol. It does require that RDAP
460 clients and servers MUST support HTTPS.
461
462 This document makes recommendations for server implementations
463 against DoS (Section 5.5) and interoperability with existing security
464 mechanisms in HTTP clients (Section 5.6).
465
466 Additional security considerations to the RDAP protocol are covered
467 in [RFC7481].
468
4698. IANA Considerations
470
4718.1. RDAP Extensions Registry
472
473 IANA has created a new category in the protocol registries labeled
474 "Registration Data Access Protocol (RDAP)", and within that category,
475 has established a URL-referenceable, stand-alone registry labeled
476 "RDAP Extensions". The purpose of this registry is to ensure
477 uniqueness of extension identifiers. The extension identifier is
478 used as a prefix in JSON names and as a prefix of path segments in
479 RDAP URLs.
480
481 The production rule for these identifiers is specified in Section 6.
482
483 In accordance with [RFC5226], the IANA policy for assigning new
484 values, shall be Specification Required: values and their meanings
485 must be documented in an RFC or in some other permanent and readily
486 available reference, in sufficient detail that interoperability
487 between independent implementations is possible.
488
489 The following is a template for an RDAP extension registration:
490
491 Extension identifier: the identifier of the extension
492
493 Registry operator: the name of the registry operator
494
495 Published specification: RFC number, bibliographical reference, or
496 URL to a permanent and readily available specification
497
498 Person & email address to contact for further information: The
499 names and email addresses of individuals to contact regarding this
500 registry entry
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510
511 Intended usage: brief reasons for this registry entry (as defined
512 by [RFC5226]).
513
514 The following is an example of a registration in the RDAP extension
515 registry:
516
517 Extension identifier: lunarNic
518
519 Registry operator: The Registry of the Moon, LLC
520
521 Published specification: http://www.example/moon_apis/rdap
522
523 Person & email address to contact for further information:
524 Professor Bernardo de la Paz <berny@moon.example>
525
526 Intended usage: COMMON
527
5289. Internationalization Considerations
529
5309.1. URIs and IRIs
531
532 Clients can use Internationalized Resource Identifiers (IRIs)
533 [RFC3987] for internal use as they see fit but MUST transform them to
534 URIs [RFC3986] for interaction with RDAP servers. RDAP servers MUST
535 use URIs in all responses, and again clients can transform these URIs
536 to IRIs for internal use as they see fit.
537
5389.2. Language Identifiers in Queries and Responses
539
540 Under most scenarios, clients requesting data will not signal that
541 the data be returned in a particular language or script. On the
542 other hand, when servers return data and have knowledge that the data
543 is in a language or script, the data SHOULD be annotated with
544 language identifiers whenever they are available, thus allowing
545 clients to process and display the data accordingly.
546
547 [RFC7483] provides such a mechanism.
548
5499.3. Language Identifiers in HTTP Headers
550
551 Given the description of the use of language identifiers in
552 Section 9.2, unless otherwise specified, servers SHOULD ignore the
553 HTTP [RFC7231] Accept-Language header field when formulating HTTP
554 entity responses, so that clients do not conflate the Accept-Language
555 header with the 'lang' values in the entity body.
556
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567 However, servers MAY return language identifiers in the Content-
568 Language header field so as to inform clients of the intended
569 language of HTTP layer messages.
570
57110. References
572
57310.1. Normative References
574
575 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
576 Requirement Levels", BCP 14, RFC 2119, March 1997,
577 <http://www.rfc-editor.org/info/rfc2119>.
578
579 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
580 Resource Identifier (URI): Generic Syntax", STD 66, RFC
581 3986, January 2005,
582 <http://www.rfc-editor.org/info/rfc3986>.
583
584 [RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource
585 Identifiers (IRIs)", RFC 3987, January 2005,
586 <http://www.rfc-editor.org/info/rfc3987>.
587
588 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
589 IANA Considerations Section in RFCs", BCP 26, RFC 5226,
590 May 2008, <http://www.rfc-editor.org/info/rfc5226>.
591
592 [RFC6585] Nottingham, M. and R. Fielding, "Additional HTTP Status
593 Codes", RFC 6585, April 2012,
594 <http://www.rfc-editor.org/info/rfc6585>.
595
596 [RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
597 Protocol (HTTP/1.1): Message Syntax and Routing", RFC
598 7230, June 2014, <http://www.rfc-editor.org/info/rfc7230>.
599
600 [RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
601 Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
602 June 2014, <http://www.rfc-editor.org/info/rfc7231>.
603
604 [RFC7481] Hollenbeck, S. and N. Kong, "Security Services for the
605 Registration Data Access Protocol (RDAP)", RFC 7481,
606 February 2015, <http://www.rfc-editor.org/info/rfc7481>.
607
608 [RFC7482] Newton, A. and S. Hollenbeck, "Registration Data Access
609 Protocol (RDAP) Query Format", RFC 7482, February 2015,
610 <http://www.rfc-editor.org/info/rfc7482>.
611
612 [RFC7483] Newton, A. and S. Hollenbeck, "JSON Responses for the
613 Registration Data Access Protocol (RDAP)", RFC 7483,
614 February 2015, <http://www.rfc-editor.org/info/rfc7483>.
615
616
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622
623 [RFC7484] Blanchet, M., "Finding the Authoritative Registration Data
624 (RDAP) Service", RFC 7484, February 2015,
625 <http://www.rfc-editor.org/info/rfc7484>.
626
627 [W3C.REC-cors-20140116]
628 Kesteren, A., "Cross-Origin Resource Sharing", W3C
629 Recommendation, REC-cors-20140116, January 2014,
630 <http://www.w3.org/TR/2014/REC-cors-20140116/>.
631
63210.2. Informative References
633
634 [REST] Fielding, R. and R. Taylor, "Principled Design of the
635 Modern Web Architecture", ACM Transactions on Internet
636 Technology, Vol. 2, No. 2, May 2002.
637
638 [RFC3912] Daigle, L., "WHOIS Protocol Specification", RFC 3912,
639 September 2004, <http://www.rfc-editor.org/info/rfc3912>.
640
641 [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
642 Specifications: ABNF", STD 68, RFC 5234, January 2008,
643 <http://www.rfc-editor.org/info/rfc5234>.
644
645 [RFC5890] Klensin, J., "Internationalized Domain Names for
646 Applications (IDNA): Definitions and Document Framework",
647 RFC 5890, August 2010,
648 <http://www.rfc-editor.org/info/rfc5890>.
649
650 [RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
651 Interchange Format", RFC 7159, March 2014,
652 <http://www.rfc-editor.org/info/rfc7159>.
653
654 [SAC-051] Piscitello, D., Ed., "SSAC Report on Domain Name WHOIS
655 Terminology and Structure", A report from the ICANN
656 Security and Stability Advisory Committee (SSAC),
657 September 2011.
658
659 [lacnic-joint-whois]
660 LACNIC, "Joint Whois", December 2005,
661 <ftp://anonymous@ftp.registro.br/pub/gter/
662 gter20/02-jwhois-lacnic.pdf>.
663
664
665
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667
668
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678
679Appendix A. Protocol Example
680
681 To demonstrate typical behavior of an RDAP client and server, the
682 following is an example of an exchange, including a redirect. The
683 data in the response has been elided for brevity, as the data format
684 is not described in this document. The media type used here is
685 described in [RFC7483].
686
687 An example of an RDAP client and server exchange:
688
689 Client:
690 <TCP connect to rdap.example.com port 80>
691 GET /rdap/ip/203.0.113.0/24 HTTP/1.1
692 Host: rdap.example.com
693 Accept: application/rdap+json
694
695 rdap.example.com:
696 HTTP/1.1 301 Moved Permanently
697 Location: http://rdap-ip.example.com/rdap/ip/203.0.113.0/24
698 Content-Length: 0
699 Content-Type: application/rdap+json
700 <TCP disconnect>
701
702 Client:
703 <TCP connect to rdap-ip.example.com port 80>
704 GET /rdap/ip/203.0.113.0/24 HTTP/1.1
705 Host: rdap-ip.example.com
706 Accept: application/rdap+json
707
708 rdap-ip.example.com:
709 HTTP/1.1 200 OK
710 Content-Type: application/rdap+json
711 Content-Length: 9001
712
713 { ... }
714 <TCP disconnect>
715
716Appendix B. Cache Busting
717
718 Some HTTP [RFC7230] cache infrastructures do not adhere to caching
719 standards adequately and could cache responses longer than is
720 intended by the server. To overcome these issues, clients can use an
721 ad hoc and improbably used query parameter with a random value of
722 their choosing. As Section 4.3 instructs servers to ignore unknown
723 parameters, this is compatible with the RDAP definition.
724
725
726
727
728
729
730Newton, et al. Standards Track [Page 13]
731
732RFC 7480 RDAP over HTTP March 2015
733
734
735 An example of using an unknown query parameter to bust caches:
736
737 http://example.com/ip/192.0.2.0?__fuhgetaboutit=xyz123
738
739 Use of an unknown parameter to overcome misbehaving caches is not
740 part of any specification and is offered here for informational
741 purposes.
742
743Appendix C. Bootstrapping and Redirection
744
745 The traditional deployment model of WHOIS [RFC3912] does not provide
746 a mechanism for determining the authoritative source for information.
747
748 Some approaches have been implemented in the past, most notably the
749 Joint WHOIS [lacnic-joint-whois] initiative. However, among other
750 shortcomings, Joint WHOIS is implemented using proxies and server-
751 side referrals.
752
753 These issues are solved in RDAP using HTTP redirects and
754 bootstrapping. Bootstrapping is discussed in [RFC7484]. In
755 constrained environments, the processes outlined in [RFC7484] may not
756 be viable, and there may be the need for servers acting as a
757 "redirector".
758
759 Redirector servers issue HTTP redirects to clients using a
760 redirection table informed by [RFC7484]. Figure 2 diagrams a client
761 using a redirector for bootstrapping.
762
763 REDIRECTOR ARIN
764 RDAP RDAP
765 . .
766 | |
767 Q: 23.1.1.1? -----------------> | |
768 | |
769 <---------- HTTP 301 --------| |
770 ('Try ARIN RDAP') | |
771 | |
772 |
773 Q: 23.1.1.1? -------------------------------> |
774 |
775 <---------- HTTP 200 --------------------- |
776 (JSON response is returned) |
777 |
778 |
779 .
780
781 Figure 2: Querying RDAP Data for 23.1.1.1
782
783
784
785
786Newton, et al. Standards Track [Page 14]
787
788RFC 7480 RDAP over HTTP March 2015
789
790
791 In some cases, particularly sub-delegations made between Regional
792 Internet Registries (RIRs) known as "ERX space" and transfers of
793 networks, multiple HTTP redirects will be issued. Figure 3 shows
794 such a scenario.
795
796 REDIRECTOR LACNIC ARIN
797 RDAP RDAP RDAP
798 . . .
799 Q: 23.1.1.1? ----> | | |
800 | | |
801 <-- HTTP 301 --- | | |
802 ('Try LACNIC') | | |
803 | | |
804 | | |
805 Q: 23.1.1.1? -----------------> | |
806 | |
807 <---------- HTTP 301 --------| |
808 ('Try ARIN RDAP') | |
809 | |
810 |
811 Q: 23.1.1.1? -------------------------------> |
812 |
813 <---------- HTTP 200 --------------------- |
814 (JSON response is returned) |
815 |
816 |
817 .
818
819 Figure 3: Querying RDAP Data for Data That Has Been Transferred
820
821Acknowledgements
822
823 John Levine provided text to tighten up the Accept header field usage
824 and the text for the section on 429 responses.
825
826 Marc Blanchet provided some clarifying text regarding the use of URLs
827 with redirects, as well as very useful feedback during Working Group
828 Last Call (WGLC).
829
830 Normative language reviews were provided by Murray S. Kucherawy,
831 Andrew Sullivan, Tom Harrison, Ed Lewis, and Alexander Mayrhofer.
832
833 Jean-Phillipe Dionne provided text for the Security Considerations
834 section.
835
836 The concept of the redirector server informatively discussed in
837 Appendix C was documented by Carlos M. Martinez and Gerardo Rada of
838
839
840
841
842Newton, et al. Standards Track [Page 15]
843
844RFC 7480 RDAP over HTTP March 2015
845
846
847 LACNIC and Linlin Zhou of CNNIC and subsequently incorporated into
848 this document.
849
850 This document is the work product of the IETF's WEIRDS working group,
851 of which Olaf Kolkman and Murray Kucherawy were chairs.
852
853Authors' Addresses
854
855 Andrew Lee Newton
856 American Registry for Internet Numbers
857 3635 Concorde Parkway
858 Chantilly, VA 20151
859 United States
860
861 EMail: andy@arin.net
862 URI: http://www.arin.net
863
864
865 Byron J. Ellacott
866 Asia Pacific Network Information Centre
867 6 Cordelia Street
868 South Brisbane QLD 4101
869 Australia
870
871 EMail: bje@apnic.net
872 URI: http://www.apnic.net
873
874
875 Ning Kong
876 China Internet Network Information Center
877 4 South 4th Street, Zhongguancun, Haidian District
878 Beijing 100190
879 China
880
881 Phone: +86 10 5881 3147
882 EMail: nkong@cnnic.cn
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898Newton, et al. Standards Track [Page 16]
899
900