Registration Protocols Extensions                            M. Loffredo
Internet-Draft                                             M. Martinelli
Intended status: Standards Track                     IIT-CNR/
Expires: April 10, 2020                                  October 8, 2019

  Registration Data Access Protocol (RDAP) Reverse search capabilities


   The Registration Data Access Protocol (RDAP) does not include query
   capabilities to find the list of domains related to a set of entities
   matching a given search pattern.  Even if such capabilities, commonly
   referred as reverse search, respond to some needs not yet readily
   fulfilled by the current Whois protocol, they have raised concerns
   from two perspectives: server processing impact and data privacy.
   Anyway, the impact of the reverse queries on RDAP servers processing
   is the same as the standard searches and it can be reduced by
   implementing policies to deal with large result sets, while data
   privacy risks can be prevented by RDAP access control
   functionalities.  This document describes RDAP query extensions that
   allow clients to request a reverse search based on the domains-
   entities relationship.

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
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   This Internet-Draft will expire on April 10, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   ( in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Conventions Used in This Document . . . . . . . . . . . .   3
   2.  RDAP Path Segment Specification . . . . . . . . . . . . . . .   4
   3.  Implementation Considerations . . . . . . . . . . . . . . . .   5
     3.1.  JSON in URLs  . . . . . . . . . . . . . . . . . . . . . .   5
   4.  Implementation Status . . . . . . . . . . . . . . . . . . . .   6
     4.1.  IIT-CNR/ . . . . . . . . . . . . . . . . . . .   7
   5.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .   7
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   Reverse Whois is a service provided by many web applications that
   allow users to find domain names owned by an individual or a company
   starting from the owner's details, such as name and email.  Even if
   it has been considered useful for some legal purposes (e.g.
   uncovering trademark infringements, detecting cybercrime cases), its
   availability as a standardized Whois capability has been objected for
   two main reasons, which now don't seem to conflict with an RDAP

   The first objection has been caused by the potential risks of privacy
   violation.  However, TLDs community is considering a new generation
   of Registration Directory Services ([ICANN-RDS1],[ICANN-RDS2]), which
   provide access to sensitive data under some permissible purposes and
   according to adequate policies to enforce the requestor
   accreditation, authentication, authorization, and terms and
   conditions of data use.  It is well known that such security policies
   are not implemented in Whois ([RFC3912]), while they are in RDAP

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   ([RFC7481]).  Therefore, RDAP permits a reverse search implementation
   complying with privacy protection principles.

   Another objection to the implementation of a reverse search
   capability has been connected with its impact on server processing.
   Since RDAP supports search queries, the impact of both standard and
   reverse searches is equivalent and can be mitigated by servers
   adopting ad hoc strategies.  Furthermore, the reverse search is
   almost always performed by specifying an entity role (e.g.
   registrant, technical contact) and this can contribute to restricting
   the result set.

   Reverse searches, such as finding the list of domain names associated
   with contacts, nameservers or DNSSEC keys, may be useful to
   registrars as well.  Usually, registries adopt out-of-band mechanisms
   to provide results to registrars asking for reverse searches on their
   domains.  Possible reasons for such requests are:

   o  the loss of synchronization between the registrar database and the
      registry database;

   o  the need for such data to perform massive EPP ([RFC5730]) updates
      (e.g. changing the contacts of a set of domains, etc.).

   Currently, RDAP does not provide any way for a client to search for
   the collection of domains associated with an entity ([RFC7482]).  A
   query (lookup or search) on domains can return the array of entities
   related to a domain with different roles (registrant, registrar,
   administrative, technical, reseller, etc.), but the reverse operation
   is not allowed.  Only reverse searches to find the collection of
   domains related to a nameserver (ldhName or ip) can be requested.
   Since entities can be in relationship with all RDAP objects
   ([RFC7483]), the availability of a reverse search can be common to
   all RDAP query paths.

   The protocol described in this specification aims to extend the RDAP
   query capabilities to enable reverse search based on the domains-
   entities relationship (the classic Reverse Whois scenario).  The
   extension is implemented by adding new path segments (i.e. search
   paths) and using a RESTful web service ([REST]).  The service is
   implemented using the Hypertext Transfer Protocol (HTTP) ([RFC7230])
   and the conventions described in RFC 7480 ([RFC7480]).

1.1.  Conventions Used in This Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in [RFC2119].

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2.  RDAP Path Segment Specification

   The new search paths are OPTIONAL extensions of path segments defined
   in RFC 7482 ([RFC7482]).  The search paths are:

      Syntax: domains?entityHandle=<reverse search pattern>

      Syntax: domains?entityFn=<reverse search pattern>

      Syntax: domains?entityEmail=<reverse search pattern>

      Syntax: domains?entityAddr=<reverse search pattern>

   The reverse search pattern is a JSON ([RFC8259]) object including two

      "value" (REQUIRED): represents the search pattern to be applied to
      the corresponding entity field and can be a JSON type primitive or

      "role" (OPTIONAL): is a string whose possible values are those
      detailed in Section 10.2.4 of RFC 7483 ([RFC7483]).  When it is
      missing, the reverse search is performed without considering the
      entity role.

   The search patterns corresponding to the "value" in the first two
   cases (Figure 1) are the same as specified in paragraph Section 3.2.3
   of RFC 7482 ([RFC7482]).



   Figure 1: Examples of RDAP queries to find all domains related to any
    registrant whose handle matches "CID-40*" and whose formatted name
                             matches "Bobby*"

   The last two reverse searches are considered by gTLD stakeholders
   very useful to improve RDS searchability ([ICANN-RDS1], [ICANN-RA]).

   Searches for domains by related entity email are specified using this


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   where XXXX is a search pattern representing an email address as
   defined in RFC 5322 ([RFC5322]).

   Searches for domains by related entity postal address are specified
   using this form:


   where YYYY is a JSON object containing the information described in
   Section 2.4 of RFC 5733 ([RFC5733]), respectively: "street", "city",
   "sp", "pc" and "cc" (Figure 2).  All the members of the postal
   address object are OPTIONAL but at least one is REQUIRED.  The
   constraints on the members are implicitly joined by AND.


   Figure 2: Example of an RDAP query to find all domains related to any
    registrant whose postal address contains the country code equals to
                   "CA" and the city equals to "Sydney"

3.  Implementation Considerations

   The implementation of the proposed extension is technically feasible.
   The search paths "handle" and "fn" are used as standard paths to
   search for entities.  With regards to the last two reverse searches,
   both email and postal address information are usually required by the
   registries but, while the former is usually mapped onto a DBMS
   indexed field, the latter is mapped onto a combination of non-indexed
   fields.  As a consequence, while the former should not significantly
   decrease the performance, the latter might have an impact on server
   processing.  Anyway, this impact is evaluated to be the same as other
   query capabilities already presented in RDAP (e.g. wildcard prefixed
   search pattern) so the risks to generate huge result sets are the
   same as those related to other standard searches and can be mitigated
   by adopting the same policies (e.g. restricting the search
   functionalities, limiting the rate of search requests according to
   the user profile, truncating and paging the results, returning
   partial responses).

3.1.  JSON in URLs

   Many web services, including RDAP, rely on the HTTP GET method to
   take advantage of some of its features:

   o  GET requests can be cached;
   o  GET requests remain in the browser history;
   o  GET requests can be bookmarked.

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   Sometimes, it happens that such advantages should be combined with
   the requirement to pass objects and arrays in the query string.  JSON
   is the best candidate as data interchange format, but it contains
   some characters that are forbidden from appearing in a URL.  Anyway,
   escaping the invalid characters is not an issue because, on the
   client side, modern browsers automatically encode URLs and, on the
   server side, several URL encoding/decoding libraries for all web
   development programming languages are available.  The downside of URL
   encoding is that it can make a pretty long URL, which, depending on
   the initial length and the number of invalid characters, might exceed
   the practical limit of web browsers (i.e. 2,000 characters).

   Other solutions to pass a JSON expression in a URL could be:

   o  converting JSON to Base64 ([RFC4648]), but binary data are

   o  using a JSON variation that complies with URL specifications and
      maintains readability like Rison ([RISON]), URLON ([URLON]) or
      JSURL ([JSURL]).

   The extensions proposed in this document rely on URL encoding because
   it is widely supported and the risk to exceed the maximum URL length
   is considered to be very unlikely in RDAP.

4.  Implementation Status

   NOTE: Please remove this section and the reference to RFC 7942 prior
   to publication as an RFC.

   This section records the status of known implementations of the
   protocol defined by this specification at the time of posting of this
   Internet-Draft, and is based on a proposal described in RFC 7942
   ([RFC7942]).  The description of implementations in this section is
   intended to assist the IETF in its decision processes in progressing
   drafts to RFCs.  Please note that the listing of any individual
   implementation here does not imply endorsement by the IETF.
   Furthermore, no effort has been spent to verify the information
   presented here that was supplied by IETF contributors.  This is not
   intended as, and must not be construed to be, a catalog of available
   implementations or their features.  Readers are advised to note that
   other implementations may exist.

   According to RFC 7942, "this will allow reviewers and working groups
   to assign due consideration to documents that have the benefit of
   running code, which may serve as evidence of valuable experimentation
   and feedback that have made the implemented protocols more mature.

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   It is up to the individual working groups to use this information as
   they see fit".

4.1.  IIT-CNR/

      Responsible Organization: Institute of Informatics and Telematics
      of National Research Council (IIT-CNR)/
      Description: This implementation includes support for RDAP queries
      using data from the public test environment of .it ccTLD.
      Level of Maturity: This is a "proof of concept" research
      Coverage: This implementation includes all of the features
      described in this specification.
      Contact Information: Mario Loffredo,

5.  Privacy Considerations

   The use of the capability described in this document MUST be
   compliant with the rules about privacy protection each RDAP provider
   is subject to.  Sensitive registration data MUST be protected and
   accessible for permissible purposes only.  Therefore, RDAP servers
   MUST provide reverse search only to those requestors who are
   authorized according to a lawful basis.  Some potential users of this
   capability include registrars searching for their own domains and
   operators in the exercise of an official authority or performing a
   specific task in the public interest that is set out in a law.
   Another scenario consists of permitting reverse searches, which take
   into account only those entities that have previously given the
   explicit consent for publishing and processing their personal data.

6.  Security Considerations

   Security services required to provide controlled access to the
   operations specified in this document are described in RFC 7481

7.  IANA Considerations

   This document has no actions for IANA.

8.  Acknowledgements

   The authors would like to acknowledge Scott Hollenbeck, Francisco
   Arias, Gustavo Lozano and Eduardo Alvarez for their contribution to
   this document.

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9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,

   [RFC3912]  Daigle, L., "WHOIS Protocol Specification", RFC 3912,
              DOI 10.17487/RFC3912, September 2004,

   [RFC5322]  Resnick, P., Ed., "Internet Message Format", RFC 5322,
              DOI 10.17487/RFC5322, October 2008,

   [RFC5730]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
              STD 69, RFC 5730, DOI 10.17487/RFC5730, August 2009,

   [RFC5733]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)
              Contact Mapping", STD 69, RFC 5733, DOI 10.17487/RFC5733,
              August 2009, <>.

   [RFC7230]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Message Syntax and Routing",
              RFC 7230, DOI 10.17487/RFC7230, June 2014,

   [RFC7480]  Newton, A., Ellacott, B., and N. Kong, "HTTP Usage in the
              Registration Data Access Protocol (RDAP)", RFC 7480,
              DOI 10.17487/RFC7480, March 2015,

   [RFC7481]  Hollenbeck, S. and N. Kong, "Security Services for the
              Registration Data Access Protocol (RDAP)", RFC 7481,
              DOI 10.17487/RFC7481, March 2015,

   [RFC7482]  Newton, A. and S. Hollenbeck, "Registration Data Access
              Protocol (RDAP) Query Format", RFC 7482,
              DOI 10.17487/RFC7482, March 2015,

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   [RFC7483]  Newton, A. and S. Hollenbeck, "JSON Responses for the
              Registration Data Access Protocol (RDAP)", RFC 7483,
              DOI 10.17487/RFC7483, March 2015,

   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", STD 90, RFC 8259,
              DOI 10.17487/RFC8259, December 2017,

9.2.  Informative References

              Internet Corporation For Assigned Names and Numbers,
              "Registry Agreement", July 2017,

              Internet Corporation For Assigned Names and Numbers,
              "Final Report from the Expert Working Group on gTLD
              Directory Services: A Next-Generation Registration
              Directory Service (RDS)", June 2014,

              Internet Corporation For Assigned Names and Numbers,
              "Final Issue Report on a Next-Generation gTLD RDS to
              Replace WHOIS", October 2015,

   [JSURL], "JSURL", 2016,

   [REST]     Fielding, R., "Architectural Styles and the Design of
              Network-based Software Architectures", 2000,

   [RFC4648]  Josefsson, S., "The Base16, Base32, and Base64 Data
              Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,

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   [RFC7942]  Sheffer, Y. and A. Farrel, "Improving Awareness of Running
              Code: The Implementation Status Section", BCP 205,
              RFC 7942, DOI 10.17487/RFC7942, July 2016,

   [RISON], "Rison - Compact Data in URIs", 2017,

   [URLON], "URL Object Notation", 2017,

Appendix A.  Change Log

   00:  Initial working group version ported from draft-loffredo-regext-
   01:  Updated "Privacy Considerations" section.
   02:  Revised the text.

Authors' Addresses

   Mario Loffredo
   Via Moruzzi,1
   Pisa  56124


   Maurizio Martinelli
   Via Moruzzi,1
   Pisa  56124


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