7Internet Engineering Task Force (IETF) S. Hollenbeck
8Request for Comments: 7481 Verisign Labs
9Category: Standards Track N. Kong
14 Security Services for the Registration Data Access Protocol (RDAP)
18 The Registration Data Access Protocol (RDAP) provides "RESTful" web
19 services to retrieve registration metadata from Domain Name and
20 Regional Internet Registries. This document describes information
21 security services, including access control, authentication,
22 authorization, availability, data confidentiality, and data integrity
27 This is an Internet Standards Track document.
29 This document is a product of the Internet Engineering Task Force
30 (IETF). It represents the consensus of the IETF community. It has
31 received public review and has been approved for publication by the
32 Internet Engineering Steering Group (IESG). Further information on
33 Internet Standards is available in Section 2 of RFC 5741.
35 Information about the current status of this document, any errata,
36 and how to provide feedback on it may be obtained at
37 http://www.rfc-editor.org/info/rfc7481.
41 Copyright (c) 2015 IETF Trust and the persons identified as the
42 document authors. All rights reserved.
44 This document is subject to BCP 78 and the IETF Trust's Legal
45 Provisions Relating to IETF Documents
46 (http://trustee.ietf.org/license-info) in effect on the date of
47 publication of this document. Please review these documents
48 carefully, as they describe your rights and restrictions with respect
49 to this document. Code Components extracted from this document must
50 include Simplified BSD License text as described in Section 4.e of
51 the Trust Legal Provisions and are provided without warranty as
52 described in the Simplified BSD License.
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60RFC 7481 RDAP Security Services March 2015
65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
66 2. Conventions Used in This Document . . . . . . . . . . . . . . 2
67 2.1. Acronyms and Abbreviations . . . . . . . . . . . . . . . 3
68 3. Information Security Services and RDAP . . . . . . . . . . . 3
69 3.1. Access Control . . . . . . . . . . . . . . . . . . . . . 3
70 3.2. Authentication . . . . . . . . . . . . . . . . . . . . . 3
71 3.2.1. Federated Authentication . . . . . . . . . . . . . . 4
72 3.3. Authorization . . . . . . . . . . . . . . . . . . . . . . 6
73 3.4. Availability . . . . . . . . . . . . . . . . . . . . . . 6
74 3.5. Data Confidentiality . . . . . . . . . . . . . . . . . . 7
75 3.6. Data Integrity . . . . . . . . . . . . . . . . . . . . . 7
76 4. Privacy Threats Associated with Registration Data . . . . . . 8
77 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
78 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
79 6.1. Normative References . . . . . . . . . . . . . . . . . . 10
80 6.2. Informative References . . . . . . . . . . . . . . . . . 11
81 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 13
82 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
86 The Registration Data Access Protocol (RDAP) is specified in multiple
87 documents, including "Registration Data Access Protocol (RDAP) Query
88 Format" [RFC7482], "JSON Responses for the Registration Data Access
89 Protocol (RDAP)" [RFC7483], and "HTTP Usage in the Registration Data
90 Access Protocol (RDAP)" [RFC7480].
92 One goal of RDAP is to provide security services that do not exist in
93 the WHOIS [RFC3912] protocol, including access control,
94 authentication, authorization, availability, data confidentiality,
95 and data integrity. This document describes how each of these
96 services is achieved by RDAP using features that are available in
97 other protocol layers. Additional or alternative mechanisms can be
98 added in the future. Where applicable, informative references to
99 requirements for a WHOIS replacement service [RFC3707] are noted.
1012. Conventions Used in This Document
103 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
104 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
105 document are to be interpreted as described in [RFC2119].
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1192.1. Acronyms and Abbreviations
121 DNR: Domain Name Registry
123 HTTP: Hypertext Transfer Protocol
125 JSON: JavaScript Object Notation
127 RDAP: Registration Data Access Protocol
129 RIR: Regional Internet Registry
131 TLS: Transport Layer Security
1333. Information Security Services and RDAP
135 RDAP itself does not include native security services. Instead, RDAP
136 relies on features that are available in other protocol layers to
137 provide needed security services, including access control,
138 authentication, authorization, availability, data confidentiality,
139 and data integrity. A description of each of these security services
140 can be found in "Internet Security Glossary, Version 2" [RFC4949].
141 No requirements have been identified for other security services.
145 WHOIS does not include specific features to control access to
146 registration information. As described in the following sections,
147 RDAP includes features to identify, authenticate, and authorize
148 clients, allowing server operators to control access to information
149 based on a client's identity and associated authorizations.
150 Information returned to a client can be clearly marked with a status
151 value (see Section 10.2.2 of [RFC7483]) that identifies the access
152 granted to the client.
156 This section describes security authentication mechanisms and the
157 need for authorization policies to include them. It describes
158 requirements for the implementations of clients and servers but does
159 not dictate the policies of server operators. For example, a server
160 operator with no policy regarding differentiated or tiered access to
161 data will have no authorization mechanisms and will have no need for
162 any type of authentication. A server operator with policies on
163 differentiated access will have to construct an authorization scheme
164 and will need to follow the specified authentication requirements.
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175 WHOIS does not provide features to identify and authenticate clients.
176 As noted in Section 3.1.4.2 of "Cross Registry Internet Service
177 Protocol (CRISP) Requirements" [RFC3707], there is utility in
178 allowing server operators to offer "varying degrees of access
179 depending on policy and need." Clients have to be identified and
180 authenticated to provide that utility.
182 RDAP's authentication framework needs to accommodate anonymous access
183 as well as verification of identities using a range of authentication
184 methods and credential services. To that end, RDAP clients and
185 servers MUST implement the authentication framework specified in
186 "Hypertext Transfer Protocol (HTTP/1.1): Authentication" [RFC7235].
187 The "basic" scheme can be used to send a client's user name and
188 password to a server in plaintext, base64-encoded form. The "digest"
189 scheme can be used to authenticate a client without exposing the
190 client's plaintext password. If the "basic" scheme is used, HTTP
191 over TLS [RFC2818] MUST be used to protect the client's credentials
192 from disclosure while in transit (see Section 3.5).
194 Servers MUST support either Basic or Digest authentication; they are
195 not required to support both. Clients MUST support both to
196 interoperate with servers that support one or the other. Servers may
197 provide a login page that triggers HTTP authentication. Clients
198 should continue sending the HTTP authentication header once they
199 receive an initial 401 (Unauthorized) response from the HTTP server
200 as long as the scheme portion of the URL doesn't change.
202 The Transport Layer Security protocol [RFC5246] includes an optional
203 feature to identify and authenticate clients who possess and present
204 a valid X.509 digital certificate [RFC5280]. Support for this
207 RDAP does not impose any unique server authentication requirements.
208 The server authentication provided by TLS fully addresses the needs
209 of RDAP. In general, transports for RDAP must either provide a
210 TLS-protected transport (e.g., HTTPS) or a mechanism that provides an
211 equivalent level of server authentication.
213 Work on HTTP authentication methods continues. RDAP is designed to
214 be agile enough to support additional methods as they are defined.
2163.2.1. Federated Authentication
218 The traditional client-server authentication model requires clients
219 to maintain distinct credentials for every RDAP server. This
220 situation can become unwieldy as the number of RDAP servers
221 increases. Federated authentication mechanisms allow clients to use
222 one credential to access multiple RDAP servers and reduce client
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231 credential management complexity. RDAP MAY include a federated
232 authentication mechanism that permits a client to access multiple
233 RDAP servers in the same federation with one credential.
235 Federated authentication mechanisms used by RDAP MUST be fully
236 supported by HTTP. OAuth, OpenID, Security Assertion Markup Language
237 (SAML), and mechanisms based on Certification Authority (CA) are all
238 possible approaches to provide federated authentication. At the time
239 of this document's publication, negotiation or advertisement of
240 federated authentication services is still an undefined mechanism by
241 the noted federated authentication protocols. Developing this
242 mechanism is beyond the scope of this document.
244 The OAuth authorization framework [RFC6749] describes a method for
245 users to access protected web resources without having to hand out
246 their credentials. Instead, clients are issued access tokens by
247 authorization servers with the permission of the resource owners.
248 Using OAuth, multiple RDAP servers can form a federation, and the
249 clients can access any server in the same federation by providing one
250 credential registered in any server in that federation. The OAuth
251 authorization framework is designed for use with HTTP and thus can be
254 OpenID [OpenID] is a decentralized single sign-on authentication
255 system that allows users to log in at multiple web sites with one ID
256 instead of having to create multiple unique accounts. An end user
257 can freely choose which OpenID provider to use and can preserve their
258 Identifier if they switch OpenID providers.
260 Note that OAuth and OpenID do not consistently require data
261 confidentiality services to protect interactions between providers
262 and consumers. HTTP over TLS [RFC2818] can be used as needed to
263 provide protection against man-in-the-middle attacks.
265 SAML 2.0 [SAML] is an XML-based protocol that can be used to
266 implement web-based authentication and authorization services,
267 including single sign on. It uses security tokens containing
268 assertions to exchange information about an end user between an
269 identity provider and a service provider.
271 The Transport Layer Security protocol describes the specification of
272 a client certificate in Section 7.4.6 of [RFC5246]. Clients who
273 possess and present a valid X.509 digital certificate, issued by a
274 CA, could be identified and authenticated by a server who trusts the
275 corresponding CA. A certificate authentication method can be used to
276 achieve federated authentication in which multiple RDAP servers all
277 trust the same CAs, and then any client with a certificate issued by
278 a trusted CA can access any RDAP server in the federation. This
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287 certificate-based mechanism is supported by HTTPS and can be used
292 WHOIS does not provide services to grant different levels of access
293 to clients based on a client's authenticated identity. As noted in
294 Section 3.1.4.2 of "Cross Registry Internet Service Protocol (CRISP)
295 Requirements" [RFC3707], there is utility in allowing server
296 operators to offer "varying degrees of access depending on policy and
297 need." Access control decisions can be made once a client's identity
298 has been established and authenticated (see Section 3.2).
300 Server operators MAY offer varying degrees of access depending on
301 policy and need in conjunction with the authentication methods
302 described in Section 3.2. If such varying degrees of access are
303 supported, an RDAP server MUST provide granular access controls (that
304 is, per registration data object) in order to implement authorization
305 policies. Some examples:
307 - Clients will be allowed access only to data for which they have a
310 - Unauthenticated or anonymous access status may not yield any
313 - Full access may be granted to a special group of authenticated
316 The type of access allowed by a server will most likely vary from one
317 operator to the next. A description of the response privacy
318 considerations associated with different levels of authorization can
319 be found in Section 13 of [RFC7483].
323 An RDAP service has to be available to be useful. There are no RDAP-
324 unique requirements to provide availability, but as a general
325 security consideration, a service operator needs to be aware of the
326 issues associated with denial of service. A thorough reading of
327 "Internet Denial-of-Service Considerations" [RFC4732] is advised.
329 An RDAP service MAY use an HTTP throttling mechanism to limit the
330 number of queries that a single client can send in a given period of
331 time. If used, the server SHOULD return an HTTP 429 (Too Many
332 Requests) response code as described in "Additional HTTP Status
333 Codes" [RFC6585]. A client that receives a 429 response SHOULD
334 decrease its query rate and honor the Retry-After header field if one
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343 is present. Note that this is not a defense against
344 denial-of-service attacks, since a malicious client could ignore the
345 code and continue to send queries at a high rate. A server might use
346 another response code if it did not wish to reveal to a client that
347 rate limiting is the reason for the denial of a reply.
3493.5. Data Confidentiality
351 WHOIS does not provide the ability to protect data from inadvertent
352 disclosure while in transit. RDAP uses HTTP over TLS [RFC2818] to
353 provide that protection by encrypting all traffic sent on the
354 connection between client and server. HTTP over TLS MUST be used to
355 protect all client-server exchanges unless operational constraints
356 make it impossible to meet this requirement. It is also possible to
357 encrypt discrete objects (such as command path segments and JSON-
358 encoded response objects) at one endpoint, send them to the other
359 endpoint via an unprotected transport protocol, and decrypt the
360 object on receipt. Encryption algorithms as described in "Internet
361 Security Glossary, Version 2" [RFC4949] are commonly used to provide
362 data confidentiality at the object level.
364 There are no current requirements for object-level data
365 confidentiality using encryption. Support for this feature could be
366 added to RDAP in the future.
368 As noted in Section 3.2, the HTTP "basic" authentication scheme can
369 be used to authenticate a client. When this scheme is used, HTTP
370 over TLS MUST be used to protect the client's credentials from
371 disclosure while in transit. If the policy of the server operator
372 requires encryption to protect client-server data exchanges (such as
373 to protect non-public data that cannot be accessed without client
374 identification and authentication), HTTP over TLS MUST be used to
375 protect those exchanges.
377 A description of privacy threats that can be addressed with
378 confidentiality services can be found in Section 4. Section 10.2.2
379 of [RFC7483] describes status values that can be used to describe
380 operator actions used to protect response data from disclosure to
381 unauthorized clients.
385 WHOIS does not provide the ability to protect data from modification
386 while in transit. Web services such as RDAP commonly use HTTP over
387 TLS [RFC2818] to provide that protection by using a keyed Message
388 Authentication Code (MAC) to detect modifications. It is also
389 possible to sign discrete objects (such as command path segments and
390 JSON-encoded response objects) at one endpoint, send them to the
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399 other endpoint via a transport protocol, and validate the signature
400 of the object on receipt. Digital signature algorithms as described
401 in "Internet Security Glossary, Version 2" [RFC4949] are commonly
402 used to provide data integrity at the object level.
404 There are no current requirements for object-level data integrity
405 using digital signatures. Support for this feature could be added to
408 The most specific need for this service is to provide assurance that
409 HTTP 30x redirection hints [RFC7231] and response elements returned
410 from the server are not modified while in transit. If the policy of
411 the server operator requires message integrity for client-server data
412 exchanges, HTTP over TLS MUST be used to protect those exchanges.
4144. Privacy Threats Associated with Registration Data
416 Registration data has historically included personal data about
417 registrants. WHOIS services have historically made this information
418 available to the public, creating a privacy risk by revealing the
419 personal details of registrants. WHOIS services have not had the
420 benefit of authentication or access control mechanisms to gate access
421 to registration data. As a result of this, proxy and privacy
422 services have arisen to shield the identities of registrants.
424 The standardization of RDAP does not change or impact the data that
425 operators may require to be collected from registrants, but it
426 provides support for a number of mechanisms that may be used to
427 mitigate privacy threats to registrants should operators choose to
430 RDAP includes mechanisms that can be used to authenticate clients,
431 allowing servers to support tiered access based on local policy.
432 This means that all registration data need no longer be public, and
433 personal data or data that may be considered more sensitive can have
434 its access restricted to specifically privileged clients.
436 RDAP data structures allow servers to indicate via status values when
437 data returned to clients has been made private, redacted, obscured,
438 or registered by a proxy. "Private" means that the data is not
439 designated for public consumption. "Redacted" means that some
440 registration data fields are not being made available. "Obscured"
441 means that data has been altered for the purposes of not readily
442 revealing the actual registration information. One option that
443 operators have available to them to reduce privacy risks to
444 registrants is to adopt policies that make use of these status values
445 to restrict the registrant data shared with any or all clients
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455 according to the sensitivity of the data, the privileges of the
456 clients, or some other heuristics.
458 RDAP uses the jCard [RFC7095] standard format for entity
459 representation. Operators may find that many of the jCard fields are
460 irrelevant for registry operation purposes or that they have no
461 reason to collect information from registrants that would correspond
462 to certain fields. Operators wishing to reduce privacy risks for
463 registrants may restrict which information they collect and/or which
464 fields they populate in responses.
466 In addition to privacy risks to registrants, there are also potential
467 privacy risks for those who query registration data. For example,
468 the fact that a registry employee performs a particular query may
469 reveal information about the employee's activities that he or she
470 would have preferred to keep private. RDAP supports the use of HTTP
471 over TLS to provide privacy protection for those querying registrant
472 data as well as registrants, unless operational constraints make it
473 impossible to meet this requirement.
4755. Security Considerations
477 One of the goals of RDAP is to provide security services that do not
478 exist in the WHOIS protocol. This document describes the security
479 services provided by RDAP and associated protocol layers, including
480 authentication, authorization, availability, data confidentiality,
481 and data integrity. Non-repudiation services were also considered
482 and ultimately rejected due to a lack of requirements. There are,
483 however, currently deployed WHOIS servers that can return signed
484 responses that provide non-repudiation with proof of origin. RDAP
485 might need to be extended to provide this service in the future.
487 As an HTTP-based protocol, RDAP is susceptible to code injection
488 attacks. Code injection refers to adding code into a computer system
489 or program to alter the course of execution. There are many types of
490 code injection, including SQL injection, dynamic variable or function
491 injection, include-file injection, shell injection, and HTML-script
492 injection, among others. Data confidentiality and integrity services
493 provide a measure of defense against man-in-the-middle injection
494 attacks, but vulnerabilities in both client- and server-side software
495 make it possible for injection attacks to succeed. Consistently
496 checking and validating server credentials can help detect
497 man-in-the-middle attacks.
499 As noted in Section 3.2.1, digital certificates can be used to
500 implement federated authentication. There is a risk of too
501 promiscuous, or even rogue, CAs being included in the list of
502 acceptable CAs that the TLS server sends the client as part of the
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511 TLS client-authentication handshake and lending the appearance of
512 trust to certificates signed by those CAs. Periodic monitoring of
513 the list of CAs that RDAP servers trust for client authentication can
514 help reduce this risk.
516 The Transport Layer Security protocol [RFC5246] includes a null
517 cipher suite that does not encrypt data and thus does not provide
518 data confidentiality. This option MUST NOT be used when data
519 confidentiality services are needed. Additional considerations for
520 secure use of TLS are described in [SECURE-TLS-DTLS].
522 Data integrity services are sometimes mistakenly associated with
523 directory service operational policy requirements focused on data
524 accuracy. "Accuracy" refers to the truthful association of data
525 elements (such as names, addresses, and telephone numbers) in the
526 context of a particular directory object (such as a domain name).
527 Accuracy requirements are out of scope for this protocol.
529 Additional security considerations are described in the
530 specifications for HTTP [RFC7231], HTTP Basic and Digest access
531 authentication [RFC7235], HTTP over TLS [RFC2818], and additional
532 HTTP status codes [RFC6585]. Security considerations for federated
533 authentication systems can be found in the OAuth [RFC6749] and OpenID
534 [OpenID] specifications.
5386.1. Normative References
540 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
541 Requirement Levels", BCP 14, RFC 2119, March 1997,
542 <http://www.rfc-editor.org/info/rfc2119>.
544 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000,
545 <http://www.rfc-editor.org/info/rfc2818>.
547 [RFC6585] Nottingham, M. and R. Fielding, "Additional HTTP Status
548 Codes", RFC 6585, April 2012,
549 <http://www.rfc-editor.org/info/rfc6585>.
551 [RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
552 Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
553 June 2014, <http://www.rfc-editor.org/info/rfc7231>.
555 [RFC7235] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
556 Protocol (HTTP/1.1): Authentication", RFC 7235, June 2014,
557 <http://www.rfc-editor.org/info/rfc7235>.
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564RFC 7481 RDAP Security Services March 2015
567 [RFC7480] Newton, A., Ellacott, B., and N. Kong, "HTTP Usage in the
568 Registration Data Access Protocol (RDAP)", RFC 7480, March
569 2015, <http://www.rfc-editor.org/info/rfc7480>.
571 [RFC7482] Newton, A. and S. Hollenbeck, "Registration Data Access
572 Protocol (RDAP) Query Format", RFC 7482, March 2015,
573 <http://www.rfc-editor.org/info/rfc7482>.
575 [RFC7483] Newton, A. and S. Hollenbeck, "JSON Responses for the
576 Registration Data Access Protocol (RDAP)", RFC 7483, March
577 2015, <http://www.rfc-editor.org/info/rfc7483>.
5796.2. Informative References
581 [OpenID] OpenID Foundation, "OpenID Authentication 2.0 - Final",
582 December 2007, <http://specs.openid.net/auth/2.0>.
584 [RFC3707] Newton, A., "Cross Registry Internet Service Protocol
585 (CRISP) Requirements", RFC 3707, February 2004,
586 <http://www.rfc-editor.org/info/rfc3707>.
588 [RFC3912] Daigle, L., "WHOIS Protocol Specification", RFC 3912,
589 September 2004, <http://www.rfc-editor.org/info/rfc3912>.
591 [RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet
592 Denial-of-Service Considerations", RFC 4732, December
593 2006, <http://www.rfc-editor.org/info/rfc4732>.
595 [RFC4949] Shirey, R., "Internet Security Glossary, Version 2", FYI
596 36, RFC 4949, August 2007,
597 <http://www.rfc-editor.org/info/rfc4949>.
599 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
600 (TLS) Protocol Version 1.2", RFC 5246, August 2008,
601 <http://www.rfc-editor.org/info/rfc5246>.
603 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
604 Housley, R., and W. Polk, "Internet X.509 Public Key
605 Infrastructure Certificate and Certificate Revocation List
606 (CRL) Profile", RFC 5280, May 2008,
607 <http://www.rfc-editor.org/info/rfc5280>.
609 [RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
610 RFC 6749, October 2012,
611 <http://www.rfc-editor.org/info/rfc6749>.
613 [RFC7095] Kewisch, P., "jCard: The JSON Format for vCard", RFC 7095,
614 January 2014, <http://www.rfc-editor.org/info/rfc7095>.
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620RFC 7481 RDAP Security Services March 2015
623 [SAML] OASIS, "Security Assertion Markup Language (SAML) v2.0",
624 March 2005, <https://www.oasis-open.org/
628 Sheffer, Y., Holz, R., and P. Saint-Andre,
629 "Recommendations for Secure Use of TLS and DTLS", Work in
630 Progress, draft-ietf-uta-tls-bcp-09, February 2015.
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681 The authors would like to acknowledge the following individuals for
682 their contributions to this document: Richard Barnes, Marc Blanchet,
683 Alissa Cooper, Ernie Dainow, Spencer Dawkins, Jean-Philippe Dionne,
684 Byron Ellacott, Stephen Farrell, Tony Hansen, Peter Koch, Murray
685 Kucherawy, Barry Leiba, Andrew Newton, and Linlin Zhou.
695 EMail: shollenbeck@verisign.com
696 URI: http://www.verisignlabs.com/
700 China Internet Network Information Center
701 4 South 4th Street, Zhongguancun, Haidian District
705 Phone: +86 10 5881 3147
706 EMail: nkong@cnnic.cn
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