Extensible Provisioning Protocol (EPP) Unhandled Namespaces
draft-ietf-regext-unhandled-namespaces-08

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Document Type RFC Internet-Draft (regext WG)
Authors James Gould  , Martin Casanova 
Last updated 2021-05-29 (latest revision 2021-02-19)
Replaces draft-gould-casanova-regext-unhandled-namespaces
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Details
Network Working Group                                           J. Gould
Internet-Draft                                            VeriSign, Inc.
Intended status: Standards Track                             M. Casanova
Expires: 23 August 2021                                           SWITCH
                                                        19 February 2021

      Extensible Provisioning Protocol (EPP) Unhandled Namespaces
               draft-ietf-regext-unhandled-namespaces-08

Abstract

   The Extensible Provisioning Protocol (EPP), as defined in RFC 5730,
   includes a method for the client and server to determine the objects
   to be managed during a session and the object extensions to be used
   during a session.  The services are identified using namespace URIs,
   and an "unhandled namespace" is one that is associated with a service
   not supported by the client.  This document defines an operational
   practice that enables the server to return information associated
   with unhandled namespace URIs that is compliant with the negotiated
   services defined in RFC 5730.

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
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   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   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 23 August 2021.

Copyright Notice

   Copyright (c) 2021 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 (https://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

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   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Conventions Used in This Document . . . . . . . . . . . .   3
   2.  Unhandled Namespaces  . . . . . . . . . . . . . . . . . . . .   4
   3.  Use of EPP <extValue> for Unhandled Namespace Data  . . . . .   4
     3.1.  Unhandled Object-Level Extension  . . . . . . . . . . . .   5
     3.2.  Unhandled Command-Response Extension  . . . . . . . . . .   7
   4.  Signaling Client and Server Support . . . . . . . . . . . . .  10
   5.  Usage with General EPP Responses  . . . . . . . . . . . . . .  11
   6.  Usage with Poll Message EPP Responses . . . . . . . . . . . .  13
   7.  Implementation Considerations . . . . . . . . . . . . . . . .  16
     7.1.  Client Implementation Considerations  . . . . . . . . . .  16
     7.2.  Server Implementation Considerations  . . . . . . . . . .  16
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  17
     8.1.  XML Namespace . . . . . . . . . . . . . . . . . . . . . .  17
     8.2.  EPP Extension Registry  . . . . . . . . . . . . . . . . .  17
   9.  Implementation Status . . . . . . . . . . . . . . . . . . . .  17
     9.1.  Verisign EPP SDK  . . . . . . . . . . . . . . . . . . . .  18
     9.2.  SWITCH Automated DNSSEC Provisioning Process  . . . . . .  18
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  19
   11. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  19
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  19
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  19
     12.2.  Informative References . . . . . . . . . . . . . . . . .  20
   Appendix A.  Change History . . . . . . . . . . . . . . . . . . .  20
     A.1.  Change from 00 to 01  . . . . . . . . . . . . . . . . . .  20
     A.2.  Change from 01 to 02  . . . . . . . . . . . . . . . . . .  21
     A.3.  Change from 02 to REGEXT 00 . . . . . . . . . . . . . . .  21
     A.4.  Change from REGEXT 00 to REGEXT 01  . . . . . . . . . . .  21
     A.5.  Change from REGEXT 01 to REGEXT 02  . . . . . . . . . . .  21
     A.6.  Change from REGEXT 02 to REGEXT 03  . . . . . . . . . . .  21
     A.7.  Change from REGEXT 03 to REGEXT 04  . . . . . . . . . . .  21
     A.8.  Change from REGEXT 04 to REGEXT 05  . . . . . . . . . . .  22
     A.9.  Change from REGEXT 05 to REGEXT 06  . . . . . . . . . . .  22
     A.10. Change from REGEXT 06 to REGEXT 07  . . . . . . . . . . .  22
     A.11. Change from REGEXT 07 to REGEXT 08  . . . . . . . . . . .  22
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  23

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1.  Introduction

   The Extensible Provisioning Protocol (EPP), as defined in [RFC5730],
   includes a method for the client and server to determine the objects
   to be managed during a session and the object extensions to be used
   during a session.  The services are identified using namespace URIs.
   How should the server handle service data that needs to be returned
   in the response when the client does not support the required service
   namespace URI, which is referred to as an unhandled namespace?  An
   unhandled namespace is a significant issue for the processing of
   [RFC5730] poll messages, since poll messages are inserted by the
   server prior to knowing the supported client services, and the client
   needs to be capable of processing all poll messages.  Returning an
   unhandled namespace poll message is not compliant with the negotiated
   services defined in [RFC5730] and returning an error makes the
   unhandled namespace poll message a poison message by halting the
   processing of the poll queue.  An unhandled namespace is an issue
   also for general EPP responses when the server has information that
   it cannot return to the client due to the client's supported
   services.  The server should be able to return unhandled namespace
   information that the client can process later.  This document defines
   an operational practice that enables the server to return information
   associated with unhandled namespace URIs that is compliant with the
   negotiated services defined in [RFC5730].

1.1.  Conventions Used in This Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   XML is case sensitive.  Unless stated otherwise, XML specifications
   and examples provided in this document MUST be interpreted in the
   character case presented in order to develop a conforming
   implementation.

   In examples, "S:" represents lines returned by a protocol server.
   Indentation and white space in examples are provided only to
   illustrate element relationships and are not a required feature of
   this protocol.

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   The examples reference XML namespace prefixes that are used for the
   associated XML namespaces.  Implementations MUST NOT depend on the
   example XML namespaces and instead employ a proper namespace-aware
   XML parser and serializer to interpret and output the XML documents.
   The example namespace prefixes used and their associated XML
   namespaces include:

   "changePoll":  urn:ietf:params:xml:ns:changePoll-1.0
   "domain":  urn:ietf:params:xml:ns:domain-1.0
   "secDNS":  urn:ietf:params:xml:ns:secDNS-1.1

   In the template example XML, placeholder content is represented by
   the following variables:

   "[NAMESPACE-XML]":  XML content associated with a login service
       namespace URI.  An example is the <domain:infData> element
       content in [RFC5731].
   "[NAMESPACE-URI]":  XML namespace URI associated with the [NAMESPACE-
       XML] XML content.  An example is "urn:ietf:params:xml:ns:domain-
       1.0" in [RFC5731].

2.  Unhandled Namespaces

   An Unhandled Namespace is an XML namespace that is associated with a
   response extension that is not included in the client-specified EPP
   login services of [RFC5730].  The EPP login services consists of the
   set of XML namespace URIs included in the <objURI> or <extURI>
   elements of the [RFC5730] EPP <login> command.  The services
   supported by the server are included in the <objURI> and <extURI>
   elements of the [RFC5730] EPP <greeting>, which should be a superset
   of the login services included in the EPP <login> command.  A server
   may have information associated with a specific namespace that it
   needs to return in the response to a client.  The unhandled
   namespaces problem exists when the server has information that it
   needs to return to the client but the namespace of the information is
   not supported by the client based on the negotiated EPP <login>
   command services.

3.  Use of EPP <extValue> for Unhandled Namespace Data

   In [RFC5730], the <extValue> element is used to provide additional
   error diagnostic information, including the <value> element that
   identifies the client-provided element that caused a server error
   condition and the <reason> element containing the human-readable
   message that describes the reason for the error.  This operational
   practice extends the use of the <extValue> element for the purpose of
   returning unhandled namespace information in a successful response.

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   When a server has data to return to the client that the client does
   not support based on the login services, the server MAY return a
   successful response, with the data for each unsupported namespace
   moved into an [RFC5730] <extValue> element.  The unhandled namespace
   will not cause an error response, but the unhandled namespace data
   will instead be moved to an <extValue> element, along with a reason
   why the unhandled namespace data could not be included in the
   appropriate location of the response.  The <extValue> element XML
   will not be processed by the XML processor.  The <extValue> element
   contains the following child elements:

   <value>:  Contains a child-element with the unhandled namespace XML.
       The unhandled namespace MUST be declared in the child element or
       any containing element including the root element.  XML
       processing of the <value> element is disabled by the XML schema
       in [RFC5730], so the information can safely be returned in the
       <value> element.
   <reason>:  A formatted human-readable message that indicates the
       reason the unhandled namespace data was not returned in the
       appropriate location of the response.  The formatted reason
       SHOULD follow the Augmented Backus-Naur Form (ABNF) grammar
       [RFC5234] format: NAMESPACE-URI "not in login services", where
       NAMESPACE-URI is the unhandled XML namespace like
       "urn:ietf:params:xml:ns:domain-1.0" for [RFC5731].

   This document applies to the handling of unsupported namespaces for
   [RFC3735] object-level extensions and command-response extensions.
   This document does not apply to the handling of unsupported
   namespaces for [RFC3735] protocol-level extensions or authentication
   information extensions.  Refer to the following sections on how to
   handle an unsupported object-level extension namespace or an
   unsupported command-response extension namespace.

3.1.  Unhandled Object-Level Extension

   An object-level extension in [RFC5730] is a child element of the
   <resData> element.  If the client does not handle the namespace of
   the object-level extension, then the <resData> element is removed and
   its object-level extension child element is moved into a [RFC5730]
   <extValue> <value> element, with the namespace URI included in the
   corresponding <extValue> <reason> element.  The response becomes a
   general EPP response without the <resData> element.

   Template response for a supported object-level extension.  The
   [NAMESPACE-XML] variable represents the object-level extension XML.

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   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   S:  <response>
   S:    <result code="1000">
   S:      <msg>Command completed successfully</msg>
   S:    </result>
   S:    <resData>
   S:      [NAMESPACE-XML]
   S:    </resData>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

   Template for an unhandled namespace response for an unsupported
   object-level extension.  The [NAMESPACE-XML] variable represents the
   object-level extension XML and the [NAMESPACE-URI] variable
   represents the object-level extension XML namespace URI.

   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   S:  <response>
   S:    <result code="1000">
   S:      <msg>Command completed successfully</msg>
   S:      <extValue>
   S:        <value>
   S:          [NAMESPACE-XML]
   S:        </value>
   S:        <reason>
   S:          [NAMESPACE-URI] not in login services
   S:        </reason>
   S:      </extValue>
   S:    </result>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

   The EPP response is converted from an object response to a general
   EPP response by the server when the client does not support the
   object-level extension namespace URI.  Below is an example of
   converting the <transfer> query response example in Section 3.1.3 of
   [RFC5731] to an unhandled namespace response.

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   [RFC5731] example <transfer> query response converted into an
   unhandled namespace response:

   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   S:  <response>
   S:    <result code="1000">
   S:      <msg>Command completed successfully</msg>
   S:      <extValue>
   S:        <value>
   S:          <domain:trnData
   S:            xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
   S:            <domain:name>example.com</domain:name>
   S:            <domain:trStatus>pending</domain:trStatus>
   S:            <domain:reID>ClientX</domain:reID>
   S:            <domain:reDate>2000-06-06T22:00:00.0Z</domain:reDate>
   S:            <domain:acID>ClientY</domain:acID>
   S:            <domain:acDate>2000-06-11T22:00:00.0Z</domain:acDate>
   S:            <domain:exDate>2002-09-08T22:00:00.0Z</domain:exDate>
   S:          </domain:trnData>
   S:        </value>
   S:        <reason>
   S:          urn:ietf:params:xml:ns:domain-1.0 not in login services
   S:        </reason>
   S:      </extValue>
   S:    </result>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

3.2.  Unhandled Command-Response Extension

   A command-response extension in [RFC5730] is a child element of the
   <extension> element.  If the client does not handle the namespace of
   the command-response extension, the command-response child element is
   moved into an [RFC5730] <extValue> <value> element, with the
   namespace URI included in the corresponding <extValue> <reason>
   element.  If after moving the command-response child element there
   are no additional command-response child elements, the <extension>
   element MUST be removed.

   Template response for a supported command-response extension.  The
   [NAMESPACE-XML] variable represents the command-response extension
   XML.

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   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   S:  <response>
   S:    <result code="1000">
   S:      <msg>Command completed successfully</msg>
   S:    </result>
   S:    <extension>
   S:      [NAMESPACE-XML]
   S:    </extension>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

   Template unhandled namespace response for an unsupported command-
   response extension.  The [NAMESPACE-XML] variable represents the
   command-response extension XML and the [NAMESPACE-URI] variable
   represents the command-response extension XML namespace URI.

   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   S:  <response>
   S:    <result code="1000">
   S:      <msg>Command completed successfully</msg>
   S:      <extValue>
   S:        <value>
   S:         [NAMESPACE-XML]
   S:        </value>
   S:        <reason>
   S:          [NAMESPACE-URI] not in login services
   S:        </reason>
   S:      </extValue>
   S:    </result>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

   The EPP response is converted to an unhandled namespace response by
   moving the unhandled command-response extension from under the
   <extension> to an <extValue> element.  Below is example of converting
   the DS Data Interface <info> response example in Section 5.1.2 of
   [RFC5910] to an unhandled namespace response.

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   [RFC5910] DS Data Interface <info> response converted into an
   unhandled namespace response:

   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0"
   S:     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   S:  <response>
   S:    <result code="1000">
   S:      <msg>Command completed successfully</msg>
   S:      <extValue>
   S:        <value>
   S:          <secDNS:infData
   S:            xmlns:secDNS="urn:ietf:params:xml:ns:secDNS-1.1">
   S:            <secDNS:dsData>
   S:              <secDNS:keyTag>12345</secDNS:keyTag>
   S:              <secDNS:alg>3</secDNS:alg>
   S:              <secDNS:digestType>1</secDNS:digestType>
   S:              <secDNS:digest>49FD46E6C4B45C55D4AC</secDNS:digest>
   S:            </secDNS:dsData>
   S:          </secDNS:infData>
   S:        </value>
   S:        <reason>
   S:          urn:ietf:params:xml:ns:secDNS-1.1 not in login services
   S:        </reason>
   S:      </extValue>
   S:    </result>
   S:    <resData>
   S:      <domain:infData
   S:        xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
   S:        <domain:name>example.com</domain:name>
   S:        <domain:roid>EXAMPLE1-REP</domain:roid>
   S:        <domain:status s="ok"/>
   S:        <domain:registrant>jd1234</domain:registrant>
   S:        <domain:contact type="admin">sh8013</domain:contact>
   S:        <domain:contact type="tech">sh8013</domain:contact>
   S:        <domain:ns>
   S:          <domain:hostObj>ns1.example.com</domain:hostObj>
   S:          <domain:hostObj>ns2.example.com</domain:hostObj>
   S:        </domain:ns>
   S:        <domain:host>ns1.example.com</domain:host>
   S:        <domain:host>ns2.example.com</domain:host>
   S:        <domain:clID>ClientX</domain:clID>
   S:        <domain:crID>ClientY</domain:crID>
   S:        <domain:crDate>1999-04-03T22:00:00.0Z</domain:crDate>
   S:        <domain:upID>ClientX</domain:upID>
   S:        <domain:upDate>1999-12-03T09:00:00.0Z</domain:upDate>
   S:        <domain:exDate>2005-04-03T22:00:00.0Z</domain:exDate>
   S:        <domain:trDate>2000-04-08T09:00:00.0Z</domain:trDate>

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   S:        <domain:authInfo>
   S:          <domain:pw>2fooBAR</domain:pw>
   S:        </domain:authInfo>
   S:      </domain:infData>
   S:    </resData>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

4.  Signaling Client and Server Support

   This document does not define new EPP protocol elements but rather
   specifies an operational practice using the existing EPP protocol,
   where the client and the server can signal support for the
   operational practice using a namespace URI in the login and greeting
   extension services.  The namespace URI
   "urn:ietf:params:xml:ns:epp:unhandled-namespaces-1.0" is used to
   signal support for the operational practice.  The client includes the
   namespace URI in an <svcExtension> <extURI> element of the [RFC5730]
   <login> Command.  The server includes the namespace URI in an
   <svcExtension> <extURI> element of the [RFC5730] Greeting.

   A client that receives the namespace URI in the server's Greeting
   extension services can expect the following supported behavior by the
   server:

   1.  Support unhandled namespace object-level extensions and command-
       response extensions in EPP poll messages, per Section 6.
   2.  Support the option of unhandled namespace command-response
       extensions in general EPP responses, per Section 5.

   A server that receives the namespace URI in the client's <login>
   Command extension services can expect the following supported
   behavior by the client:

   1.  Support monitoring the EPP poll messages and general EPP
       responses for unhandled namespaces.

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5.  Usage with General EPP Responses

   The unhandled namespace approach defined in Section 3 MAY be used for
   a general EPP response to an EPP command.  A general EPP response
   includes any non-poll message EPP response.  The use of the unhandled
   namespace approach for poll message EPP responses is defined in
   Section 6.  The server MAY exclude the unhandled namespace
   information in the general EPP response or MAY include it using the
   unhandled namespace approach.

   The unhandled namespace approach for general EPP responses SHOULD
   only be applicable to command-response extensions, defined in
   Section 3.2, since the server SHOULD NOT accept an object-level EPP
   command if the client did not include the object-level namespace URI
   in the login services.  An object-level EPP response extension is
   returned when the server successfully executes an object-level EPP
   command extension.  The server MAY return an unhandled object-level
   extension to the client as defined in Section 3.1.

   Returning domain name Redemption Grace Period (RGP) data, based on
   [RFC3915], provides an example of applying the unhandled namespace
   approach for a general EPP response.  If the client does not include
   the "urn:ietf:params:xml:ns:rgp-1.0" namespace URI in the login
   services, and the domain <info> response of a domain name does have
   RGP information, the server MAY exclude the <rgp:infData> element
   from the EPP response or MAY include it under the <extValue> element
   per Section 3.2.  Below is example of converting the domain name
   <info> response example in Section 4.1.2 of [RFC3915] to an unhandled
   namespace response.

   [RFC5731] domain name <info> response with the unhandled [RFC3915]
   <rgp:infData> element included under an <extValue> element:

   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0"
   S:     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   S:     xsi:schemaLocation="urn:ietf:params:xml:ns:epp-1.0
   S:     epp-1.0.xsd">
   S:  <response>
   S:    <result code="1000">
   S:      <msg>Command completed successfully</msg>
   S:      <extValue>
   S:        <value>
   S:          <rgp:infData xmlns:rgp="urn:ietf:params:xml:ns:rgp-1.0"
   S:           xsi:schemaLocation="urn:ietf:params:xml:ns:rgp-1.0
   S:           rgp-1.0.xsd">
   S:            <rgp:rgpStatus s="redemptionPeriod"/>
   S:          </rgp:infData>

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   S:        </value>
   S:        <reason>
   S:          urn:ietf:params:xml:ns:rgp-1.0 not in login services
   S:        </reason>
   S:      </extValue>
   S:    </result>
   S:    <resData>
   S:      <domain:infData
   S:        xmlns:domain="urn:ietf:params:xml:ns:domain-1.0"
   S:        xsi:schemaLocation="urn:ietf:params:xml:ns:domain-1.0
   S:        domain-1.0.xsd">
   S:        <domain:name>example.com</domain:name>
   S:        <domain:roid>EXAMPLE1-REP</domain:roid>
   S:        <domain:status s="pendingDelete"/>
   S:        <domain:registrant>jd1234</domain:registrant>
   S:        <domain:contact type="admin">sh8013</domain:contact>
   S:        <domain:contact type="tech">sh8013</domain:contact>
   S:        <domain:ns>
   S:          <domain:hostObj>ns1.example.com</domain:hostObj>
   S:          <domain:hostObj>ns1.example.net</domain:hostObj>
   S:        </domain:ns>
   S:        <domain:host>ns1.example.com</domain:host>
   S:        <domain:host>ns2.example.com</domain:host>
   S:        <domain:clID>ClientX</domain:clID>
   S:        <domain:crID>ClientY</domain:crID>
   S:        <domain:crDate>1999-04-03T22:00:00.0Z</domain:crDate>
   S:        <domain:upID>ClientX</domain:upID>
   S:        <domain:upDate>1999-12-03T09:00:00.0Z</domain:upDate>
   S:        <domain:exDate>2005-04-03T22:00:00.0Z</domain:exDate>
   S:        <domain:trDate>2000-04-08T09:00:00.0Z</domain:trDate>
   S:        <domain:authInfo>
   S:          <domain:pw>2fooBAR</domain:pw>
   S:        </domain:authInfo>
   S:      </domain:infData>
   S:    </resData>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

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6.  Usage with Poll Message EPP Responses

   The unhandled namespace approach, defined in Section 3, MUST be used
   if there is unhandled namespace information included in an EPP <poll>
   message response.  The server inserts poll messages into the client's
   poll queue independent of knowing the supported client login
   services, therefore there may be unhandled object-level and command-
   response extensions included in a client's poll queue.  In [RFC5730],
   the <poll> command is used by the client to retrieve and acknowledge
   poll messages that have been inserted by the server.  The <poll>
   message response is an EPP response that includes the <msgQ> element
   that provides poll queue meta-data about the message.  The unhandled
   namespace approach, defined in Section 3, is used for an unhandled
   object-level extension and for each of the unhandled command-response
   extensions attached to the <poll> message response.  The resulting
   EPP <poll> message response MAY have either or both the object-level
   extension or command-response extensions moved to <extValue>
   elements, as defined in Section 3.

   The Change Poll Message, as defined in Section 3.1.2 of [RFC8590],
   which is an extension of any EPP object, is an example of applying
   the unhandled namespace approach for EPP <poll> message responses.
   Below are examples of converting the domain name <info> response
   example in Section 3.1.2 of [RFC8590] to an unhandled namespace
   response.  The object that will be used in the examples is a
   [RFC5731] domain name object.

   [RFC5731] domain name <info> <poll> message response with the
   unhandled [RFC8590] <changePoll:changeData> element included under an
   <extValue> element:

   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   S:  <response>
   S:    <result code="1301">
   S:      <msg lang="en-US">
   S:        Command completed successfully; ack to dequeue</msg>
   S:      <extValue>
   S:        <value>
   S:          <changePoll:changeData
   S:           xmlns:changePoll="urn:ietf:params:xml:ns:changePoll-1.0"
   S:           state="after">
   S:            <changePoll:operation>update</changePoll:operation>
   S:            <changePoll:date>
   S:              2013-10-22T14:25:57.0Z</changePoll:date>
   S:            <changePoll:svTRID>12345-XYZ</changePoll:svTRID>
   S:            <changePoll:who>URS Admin</changePoll:who>
   S:            <changePoll:caseId type="urs">urs123

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   S:            </changePoll:caseId>
   S:            <changePoll:reason>URS Lock</changePoll:reason>
   S:          </changePoll:changeData>
   S:        </value>
   S:        <reason>
   S:        urn:ietf:params:xml:ns:changePoll-1.0 not in login services
   S:        </reason>
   S:      </extValue>
   S:    </result>
   S:    <msgQ count="201" id="1">
   S:      <qDate>2013-10-22T14:25:57.0Z</qDate>
   S:      <msg>Registry initiated update of domain.</msg>
   S:    </msgQ>
   S:    <resData>
   S:      <domain:infData
   S:        xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
   S:        <domain:name>domain.example</domain:name>
   S:        <domain:roid>EXAMPLE1-REP</domain:roid>
   S:        <domain:status s="ok"/>
   S:        <domain:registrant>jd1234</domain:registrant>
   S:        <domain:contact type="admin">sh8013</domain:contact>
   S:        <domain:contact type="tech">sh8013</domain:contact>
   S:        <domain:clID>ClientX</domain:clID>
   S:        <domain:crID>ClientY</domain:crID>
   S:        <domain:crDate>2012-04-03T22:00:00.0Z</domain:crDate>
   S:        <domain:exDate>2014-04-03T22:00:00.0Z</domain:exDate>
   S:      </domain:infData>
   S:    </resData>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

   Unhandled [RFC5731] domain name <info> <poll> message response and
   the unhandled [RFC8590] <changePoll:changeData> element included
   under an <extValue> element:

   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   S:  <response>
   S:    <result code="1301">
   S:      <msg>Command completed successfully; ack to dequeue</msg>
   S:      <extValue>
   S:        <value>
   S:          <domain:infData
   S:            xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">

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   S:            <domain:name>domain.example</domain:name>
   S:            <domain:roid>EXAMPLE1-REP</domain:roid>
   S:            <domain:status s="ok"/>
   S:            <domain:registrant>jd1234</domain:registrant>
   S:            <domain:contact type="admin">sh8013</domain:contact>
   S:            <domain:contact type="tech">sh8013</domain:contact>
   S:            <domain:clID>ClientX</domain:clID>
   S:            <domain:crID>ClientY</domain:crID>
   S:            <domain:crDate>2012-04-03T22:00:00.0Z</domain:crDate>
   S:            <domain:exDate>2014-04-03T22:00:00.0Z</domain:exDate>
   S:          </domain:infData>
   S:        </value>
   S:        <reason>
   S:          urn:ietf:params:xml:ns:domain-1.0 not in login services
   S:        </reason>
   S:      </extValue>
   S:      <extValue>
   S:        <value>
   S:          <changePoll:changeData
   S:            xmlns:changePoll=
   S:              "urn:ietf:params:xml:ns:changePoll-1.0"
   S:            state="after">
   S:            <changePoll:operation>update</changePoll:operation>
   S:            <changePoll:date>
   S:              2013-10-22T14:25:57.0Z</changePoll:date>
   S:            <changePoll:svTRID>12345-XYZ</changePoll:svTRID>
   S:            <changePoll:who>URS Admin</changePoll:who>
   S:            <changePoll:caseId type="urs">urs123
   S:            </changePoll:caseId>
   S:            <changePoll:reason>URS Lock</changePoll:reason>
   S:          </changePoll:changeData>
   S:        </value>
   S:        <reason>
   S:        urn:ietf:params:xml:ns:changePoll-1.0 not in login services
   S:        </reason>
   S:      </extValue>
   S:    </result>
   S:    <msgQ count="201" id="1">
   S:      <qDate>2013-10-22T14:25:57.0Z</qDate>
   S:      <msg>Registry initiated update of domain.</msg>
   S:    </msgQ>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

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7.  Implementation Considerations

   There are implementation considerations for the client and the server
   to help address the risk of the client ignoring unhandled namespace
   information included in an EPP response that is needed to meet
   technical, policy, or legal requirements.

7.1.  Client Implementation Considerations

   To reduce the likelihood of a client receiving unhandled namespace
   information, the client should consider implementing the following:

   1.  Ensure that the client presents the complete set of what it
       supports when presenting its login services.  If there are gaps
       between the services supported by the client and the login
       services included in the login command, the client may receive
       unhandled namespace information that the client could have
       supported.
   2.  Support all of the services included in the server greeting
       services that may be included in an EPP response, including the
       poll queue responses.  The client should evaluate the gaps
       between the greeting services and the login services provided in
       the login command to identify extensions that need to be
       supported.
   3.  Proactively monitor for unhandled namespace information in the
       EPP responses by looking for the inclusion of the <extValue>
       element in successful responses, recording the unsupported
       namespace included in the <reason> element, and recording the
       unhandled namespace information included in the <value> element
       for later processing.  The unhandled namespace should be
       implemented by the client to ensure that information is processed
       fully in future EPP responses.

7.2.  Server Implementation Considerations

   To assist the clients in recognizing unhandled namespaces, the server
   should consider implementing the following:

   1.  Monitor for returning unhandled namespace information to clients
       and report it to the clients out-of-band to EPP so the clients
       can add support for the unhandled namespaces.
   2.  Look for the unhandled namespace support in the login services
       when returning optional unhandled namespace information in
       General EPP Responses.

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8.  IANA Considerations

8.1.  XML Namespace

   This document uses URNs to describe XML namespaces conforming to a
   registry mechanism described in [RFC3688].  The following URI
   assignment is requested of IANA:

   Registration request for the unhandled namespaces namespace:

      URI: urn:ietf:params:xml:ns:epp:unhandled-namespaces-1.0
      Registrant Contact: IESG
      XML: None.  Namespace URIs do not represent an XML specification.

8.2.  EPP Extension Registry

   The EPP operational practice described in this document should be
   registered by the IANA in the EPP Extension Registry described in
   [RFC7451].  The details of the registration are as follows:

   Name of Extension: "Extensible Provisioning Protocol (EPP) Unhandled
   Namespaces"

   Document status: Standards Track

   Reference: (insert reference to RFC version of this document)

   Registrant Name and Email Address: IETF, <iesg@ietf.org>

   TLDs: Any

   IPR Disclosure: None

   Status: Active

   Notes: None

9.  Implementation Status

   Note to RFC Editor: Please remove this section and the reference to
   RFC 7942 [RFC7942] before publication.

   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

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   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 [RFC7942], "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.  It is up to the individual working groups to use this
   information as they see fit".

9.1.  Verisign EPP SDK

   Organization: Verisign Inc.

   Name: Verisign EPP SDK

   Description: The Verisign EPP SDK includes an implementation of the
   unhandled namespaces for the processing of the poll queue messages.

   Level of maturity: Development

   Coverage: All aspects of the protocol are implemented.

   Licensing: GNU Lesser General Public License

   Contact: jgould@verisign.com

   URL: https://www.verisign.com/en_US/channel-resources/domain-
   registry-products/epp-sdks

9.2.  SWITCH Automated DNSSEC Provisioning Process

   Organization: SWITCH

   Name: Registry of .CH and .LI

   Description: SWITCH uses poll messages to inform the registrar about
   DNSSEC changes at the registry triggered by CDS records.  These poll
   messages are enriched with the 'urn:ietf:params:xml:ns:changePoll-
   1.0' and the 'urn:ietf:params:xml:ns:secDNS-1.1' extension that are
   rendered in the poll msg response according to this draft.

   Level of maturity: Operational

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   Coverage: All aspects of the protocol are implemented.

   Licensing: Proprietary

   Contact: martin.casanova@switch.ch

   URL: https://www.nic.ch/cds

10.  Security Considerations

   This document does not provide any security services beyond those
   described by EPP [RFC5730] and protocol layers used by EPP.  The
   security considerations described in these other specifications apply
   to this specification as well.  Since the unhandled namespace context
   is XML that is not processed in the first pass by the XML parser, the
   client SHOULD validate the XML when the content is processed to
   protect against the inclusion of malicious content.

11.  Acknowledgements

   The authors wish to thank the following persons for their feedback
   and suggestions: Thomas Corte, Scott Hollenbeck, Patrick Mevzek, and
   Marcel Parodi.

12.  References

12.1.  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,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234,
              DOI 10.17487/RFC5234, January 2008,
              <https://www.rfc-editor.org/info/rfc5234>.

   [RFC5730]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
              STD 69, RFC 5730, DOI 10.17487/RFC5730, August 2009,
              <https://www.rfc-editor.org/info/rfc5730>.

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   [RFC5731]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)
              Domain Name Mapping", STD 69, RFC 5731,
              DOI 10.17487/RFC5731, August 2009,
              <https://www.rfc-editor.org/info/rfc5731>.

   [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,
              <https://www.rfc-editor.org/info/rfc7942>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

12.2.  Informative References

   [RFC3735]  Hollenbeck, S., "Guidelines for Extending the Extensible
              Provisioning Protocol (EPP)", RFC 3735,
              DOI 10.17487/RFC3735, March 2004,
              <https://www.rfc-editor.org/info/rfc3735>.

   [RFC3915]  Hollenbeck, S., "Domain Registry Grace Period Mapping for
              the Extensible Provisioning Protocol (EPP)", RFC 3915,
              DOI 10.17487/RFC3915, September 2004,
              <https://www.rfc-editor.org/info/rfc3915>.

   [RFC5910]  Gould, J. and S. Hollenbeck, "Domain Name System (DNS)
              Security Extensions Mapping for the Extensible
              Provisioning Protocol (EPP)", RFC 5910,
              DOI 10.17487/RFC5910, May 2010,
              <https://www.rfc-editor.org/info/rfc5910>.

   [RFC7451]  Hollenbeck, S., "Extension Registry for the Extensible
              Provisioning Protocol", RFC 7451, DOI 10.17487/RFC7451,
              February 2015, <https://www.rfc-editor.org/info/rfc7451>.

   [RFC8590]  Gould, J. and K. Feher, "Change Poll Extension for the
              Extensible Provisioning Protocol (EPP)", RFC 8590,
              DOI 10.17487/RFC8590, May 2019,
              <https://www.rfc-editor.org/info/rfc8590>.

Appendix A.  Change History

A.1.  Change from 00 to 01

   1.  Removed xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       reference from examples.
   2.  removed <extension></extension> block from example.

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   3.  added SWITCH Automated DNSSEC Provisioning Process at
       Implementation Status

A.2.  Change from 01 to 02

   1.  Ping update

A.3.  Change from 02 to REGEXT 00

   1.  Changed to regext working group draft by changing draft-gould-
       casanova-regext-unhandled-namespaces to draft-ietf-regext-
       unhandled-namespaces.

A.4.  Change from REGEXT 00 to REGEXT 01

   1.  Added the "Signaling Client and Server Support" section to
       describe the mechanism to signal support for the BCP by the
       client and the server.
   2.  Added the IANA Considerations section with the registration of
       the unhandled namespaces XML namespace and the registration of
       the EPP Best Current Practice (BCP) in the EPP Extension
       Registry.

A.5.  Change from REGEXT 01 to REGEXT 02

   1.  Filled in the acknowledgements section.
   2.  Changed the reference from RFC 5730 to RFC 5731 for the transfer
       example in section 3.1 "Unhandled Object-Level" Extension.
   3.  Updated the XML namespace to
       urn:ietf:params:xml:ns:epp:unhandled-namespaces-1.0, which
       removed bcp from the namespace and bumped the version from 0.1
       and 1.0.  Inclusion of bcp in the XML namespace was discussed at
       the REGEXT interim meeting.

A.6.  Change from REGEXT 02 to REGEXT 03

   1.  Converted from xml2rfc v2 to v3.
   2.  Updated Acknowledgements to match the approach taken by the RFC
       Editor with draft-ietf-regext-login-security.
   3.  Changed reference of ietf-regext-change-poll to RFC 8590.

A.7.  Change from REGEXT 03 to REGEXT 04

   1.  Changed from Best Current Practice (BCP) to Standards Track based
       on mailing list discussion.
   2.  Revised the dates in the examples to be more up-to-date.

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A.8.  Change from REGEXT 04 to REGEXT 05

   1.  Based on feedback from Thomas Corte, added a description of the
       <extValue> element in RFC 5730 and it being extended to support
       returning unhandled namespace information.
   2.  Based on feedback from Thomas Corte, added a Implementation
       Considerations section to cover client and server implementation
       recommendations such as monitoring unhandled namespaces in the
       server to report to the clients out-of-band and monitoring for
       responses containing unhanded namespace information in the client
       to proactively add support for the unhandled namespaces.
   3.  Moved RFC 3735 and RFC 7451 to informative references to address
       down reference errors in idnits.

A.9.  Change from REGEXT 05 to REGEXT 06

   1.  Nit updates made based on the feedback provided by the Document
       Shepherd, David Smith.

A.10.  Change from REGEXT 06 to REGEXT 07

   Updates based on the Barry Leiba (AD) feedback:

   1.  Simplified the abstract based on the proposal provided by the AD.
   2.  In section 1.1, updated to use the new BCP 14 boilerplate and add
       a normative reference to RFC 8174.
   3.  In section 1.1, changed "REQUIRED feature of this protocol" to
       "required feature of this protocol".
   4.  In section 3, added "by the XML schema" in "disabled by the XML
       schema in [RFC5730]" to clarify the statement.
   5.  In section 8.2, changed the Registrant Name from "IESG" to
       "IETF".
   6.  In section 10, changed "The document do not provide" to "This
       document does not provide".
   7.  In section 10, added the sentence "Since the unhandled namespace
       context is XML that is not processed in the first pass by the XML
       parser, the client SHOULD consider validating the XML when the
       content is processed to protect against the inclusion of
       malicious content.".

A.11.  Change from REGEXT 07 to REGEXT 08

   1.  Nit updates made based on the feedback provided by Peter Yee.
   2.  Update to the definition of the <value> element based on feedback
       from Sabrina Tanamal.
   3.  Added a sentence in the Introduction section to cover the poison
       poll message motivation based on feedback from Qin Wu.

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   4.  Changed "does not define new protocol" to "does not define new
       EPP protocol elements" based on feedback from Erik Kline.
   5.  Changed to use "apply" instead of "support" language in Section 3
       based on feedback from Benjamin Kaduk.
   6.  Updated the examples that reference RFC examples to reference the
       RFC section of the example and have the starting XML match based
       on feedback from Benjamin Kaduk.
   7.  Changed "SHOULD consider validating" to "SHOULD validate" in the
       Security Considerations section based on feedback from Benjamin
       Kaduk.
   8.  Moved RFC 3915, RFC 5910, and RFC 8590 as informational
       references based on feedback from Benjamin Kaduk.

Authors' Addresses

   James Gould
   VeriSign, Inc.
   12061 Bluemont Way
   Reston, VA 20190
   United States of America

   Email: jgould@verisign.com
   URI:   http://www.verisigninc.com

   Martin Casanova
   SWITCH
   P.O. Box
   CH-8021 Zurich
   Switzerland

   Email: martin.casanova@switch.ch
   URI:   http://www.switch.ch

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