New protocol elements for HTTP Status Code 451
draft-sahib-451-new-protocol-elements-02

Network Working Group                                           S. Sahib
Internet-Draft                                             July 16, 2018
Intended status: Informational
Expires: January 17, 2019

             New protocol elements for HTTP Status Code 451
                draft-sahib-451-new-protocol-elements-02

Abstract

   This document recommends additional protocol elements to Hypertext
   Transfer Protocol (HTTP) status code 451 (defined by RFC7725).

   Discussion of this document was conducted on the Human Rights
   Protocol Considerations Research Group mailing list
   https://www.irtf.org/mailman/listinfo/hrpc [1], briefly on the
   HTTPBIS Working Group mailing list ietf-http-wg@w3.org [2] and on
   https://lists.ghserv.net/mailman/listinfo/statuscode451 [3].

Status of This Memo

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   This Internet-Draft will expire on January 17, 2019.

Copyright Notice

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   document authors.  All rights reserved.

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   include Simplified BSD License text as described in Section 4.e of
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  New Protocol Elements . . . . . . . . . . . . . . . . . . . .   2
     2.1.  Blocking Authority  . . . . . . . . . . . . . . . . . . .   2
     2.2.  Geographical Scope of Block . . . . . . . . . . . . . . .   3
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   3
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   4
     6.3.  URIs  . . . . . . . . . . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   [RFC7725] was standardized by the IETF in February 2016.  It defined
   HTTP status code 451 - to be used when "a server operator has
   received a legal demand to deny access to a resource or to a set of
   resources".

   This document attempts to outline protocol recommendations that would
   help make the status code more useful to users.

2.  New Protocol Elements

2.1.  Blocking Authority

   In addition to the "blocked-by" header specified in [RFC7725], an
   HTTP response with status code 451 would benefit from including
   another "Link" HTTP header field [RFC5988] which has a "rel"
   parameter whose value is "blocking-authority".  It's important to
   distinguish between the implementer of the block, and the authority
   that mandated the block in the first place.  This is because these
   two organizations might not be the same - a government (the blocking
   authority) could force an Internet Service Provider (the implementer
   of the block) to deny access to a certain resource.  There is
   confusion amongst implementors of [RFC7725] about the meaning of the
   term "blocked-by", perhaps in part because of the example given in
   the RFC [ERRATA_ID-5181] - it would be useful to explicitly include
   space for both, as both provide essential information about the legal
   block.

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2.2.  Geographical Scope of Block

   HTTP status code 451 is increasingly being used to deny access to
   resources based on geographical IP.  The response should contain a
   provisional header with geographical scope of block.  This scope
   should correspond to comma-separated list of alpha-2 country codes
   defined in [ISO.3166-1].  The rationale for keeping the geographical
   scope to country-level granularity is that most blocks are mandated
   by national governments [IMPL_REPORT],
   [AUTOMATTIC_COUNTRY_BLOCK_LIST].  In addition, as the serving of this
   status code is voluntary, there is value in not complicating the
   specification.

3.  Security Considerations

   This document does not add additional security considerations to
   [RFC7725].

4.  IANA Considerations

   The Link Relation Type Registry should be updated with the following
   entry:

   -  Relation Name: blocking-authority

   -  Description: Identifies the authority that has issued the block.

   -  Reference: this document

   In addition, IANA should be updated with the following provisional
   header:

   -  Header field name: geo-scope-block

   -  Applicable protocol: http

   -  Status: provisional

   -  Specification document(s): this document

Acknowledgements

   Thanks to Alp Toker, Christine Runnegar, Niels ten Oever, Stephane
   Bortzmeyer, Corinne Cath and many others on the HRPC mailing list
   (linked above) for reviewing and brainstorming.

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6.  References

6.1.  Normative References

   [ERRATA_ID-5181]
              Bortzmeyer, S., "[Technical Errata Reported] RFC7725
              (5181)", 2017,
              <https://www.rfc-editor.org/errata/eid5181>.

   [ISO.3166-1]
              International Organization for Standardization, "Codes for
              the representation of names of countries and their
              subdivisions - Part 1: Country code", ISO Standard 3166-
              1:1997 , 1997.

   [RFC2277]  Alvestrand, H., "IETF Policy on Character Sets and
              Languages", BCP 18, RFC 2277, DOI 10.17487/RFC2277,
              January 1998, <https://www.rfc-editor.org/info/rfc2277>.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <https://www.rfc-editor.org/info/rfc3986>.

   [RFC5988]  Nottingham, M., "Web Linking", RFC 5988,
              DOI 10.17487/RFC5988, October 2010,
              <https://www.rfc-editor.org/info/rfc5988>.

   [RFC7725]  Bray, T., "An HTTP Status Code to Report Legal Obstacles",
              RFC 7725, DOI 10.17487/RFC7725, February 2016,
              <https://www.rfc-editor.org/info/rfc7725>.

   [RFC8280]  ten Oever, N. and C. Cath, "Research into Human Rights
              Protocol Considerations", RFC 8280, DOI 10.17487/RFC8280,
              October 2017, <https://www.rfc-editor.org/info/rfc8280>.

   [RFC8288]  Nottingham, M., "Web Linking", RFC 8288,
              DOI 10.17487/RFC8288, October 2017,
              <https://www.rfc-editor.org/info/rfc8288>.

6.2.  Informative References

   [AUTOMATTIC_COUNTRY_BLOCK_LIST]
              "Automattic - Country Block List", 2018,
              <https://transparency.automattic.com/country-block-list/>.

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   [IMPL_REPORT]
              Abraham, S., Canales, MP., Hall, J., Khrustaleva, O., ten
              Oever, N., Runnegar, C., and S. Sahib, "Implementation
              Report for HTTP Status Code 451", 2017,
              <https://tools.ietf.org/html/draft-451-imp-report-00>.

6.3.  URIs

   [1] https://www.irtf.org/mailman/listinfo/hrpc

   [2] mailto:ietf-http-wg@w3.org

   [3] https://lists.ghserv.net/mailman/listinfo/statuscode451

Author's Address

   Shivan Kaul Sahib

   EMail: shivankaulsahib@gmail.com

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