



Network Working Group                                      D. Belyavskiy
Internet-Draft                                                          
Intended status: Standards Track                                J. Gould
Expires: 3 April 2025                                     VeriSign, Inc.
                                                           S. Hollenbeck
                                                           Verisign Labs
                                                       30 September 2024


Use of Internationalized Email Addresses in the Extensible Provisioning
                             Protocol (EPP)
                      draft-ietf-regext-epp-eai-22

Abstract

   The Extensible Provisioning Protocol (EPP) does not natively support
   internationalized email addresses because the specifications for
   these addresses did not exist when EPP was developed.  This document
   describes a command-response extension that adds support for
   associating either an internationalized email address or a second
   all-ASCII address with an EPP contact object and specifies how these
   addresses can be used by EPP clients and servers.

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   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 3 April 2025.

Copyright Notice

   Copyright (c) 2024 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.



Belyavskiy, et al.        Expires 3 April 2025                  [Page 1]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Conventions Used in This Document . . . . . . . . . . . .   4
   2.  Migrating to Newer Versions of This Extension . . . . . . . .   4
   3.  Email Address Specification . . . . . . . . . . . . . . . . .   4
   4.  Additional Email Address Element  . . . . . . . . . . . . . .   5
   5.  Extension Considerations  . . . . . . . . . . . . . . . . . .   5
     5.1.  Signaling Client and Server Support . . . . . . . . . . .   5
     5.2.  Extension Behavior  . . . . . . . . . . . . . . . . . . .   5
       5.2.1.  Extension Negotiated  . . . . . . . . . . . . . . . .   5
       5.2.2.  Extension Not Negotiated  . . . . . . . . . . . . . .   6
   6.  EPP Command Mapping . . . . . . . . . . . . . . . . . . . . .   6
     6.1.  EPP Query Commands  . . . . . . . . . . . . . . . . . . .   6
       6.1.1.  EPP <check> Command . . . . . . . . . . . . . . . . .   6
       6.1.2.  EPP <info> Command  . . . . . . . . . . . . . . . . .   7
       6.1.3.  EPP <transfer> Query Command  . . . . . . . . . . . .  11
     6.2.  EPP Transform Commands  . . . . . . . . . . . . . . . . .  11
       6.2.1.  EPP <create> Command  . . . . . . . . . . . . . . . .  11
       6.2.2.  EPP <delete> Command  . . . . . . . . . . . . . . . .  14
       6.2.3.  EPP <renew> Command . . . . . . . . . . . . . . . . .  14
       6.2.4.  EPP <transfer> Command  . . . . . . . . . . . . . . .  14
       6.2.5.  EPP <update> Command  . . . . . . . . . . . . . . . .  14
   7.  Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . .  16
     7.1.  EPP Additional Email Address Extension Schema . . . . . .  16
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  17
     8.1.  XML Namespace . . . . . . . . . . . . . . . . . . . . . .  17
     8.2.  EPP Extension Registry  . . . . . . . . . . . . . . . . .  18
   9.  Implementation Status . . . . . . . . . . . . . . . . . . . .  18
     9.1.  Verisign EPP SDK  . . . . . . . . . . . . . . . . . . . .  19
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  19
   11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  20
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  20
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  20
     12.2.  Informative References . . . . . . . . . . . . . . . . .  21
   Appendix A.  Change History . . . . . . . . . . . . . . . . . . .  22
     A.1.  Change from 00 to 01  . . . . . . . . . . . . . . . . . .  22
     A.2.  Change from 01 to 02  . . . . . . . . . . . . . . . . . .  22
     A.3.  Change from 02 to 03  . . . . . . . . . . . . . . . . . .  22
     A.4.  Change from 03 to 04  . . . . . . . . . . . . . . . . . .  22
     A.5.  Change from 04 to the regext 01 version . . . . . . . . .  22
     A.6.  Change from the regext 01 to regext 02 version  . . . . .  23



Belyavskiy, et al.        Expires 3 April 2025                  [Page 2]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


     A.7.  Change from the regext 02 to regext 03 version  . . . . .  23
     A.8.  Change from the regext 03 to regext 04 version  . . . . .  23
     A.9.  Change from the regext 04 to regext 05 version  . . . . .  23
     A.10. Change from the regext 05 to regext 06 version  . . . . .  23
     A.11. Change from the regext 06 to regext 07 version  . . . . .  23
     A.12. Change from the regext 07 to regext 08 version  . . . . .  23
     A.13. Change from the regext 08 to regext 09 version  . . . . .  23
     A.14. Change from the regext 09 to regext 10 version  . . . . .  24
     A.15. Change from the regext 10 to regext 11 version  . . . . .  24
     A.16. Change from the regext 11 to regext 12 version  . . . . .  24
     A.17. Change from the regext 12 to regext 13 version  . . . . .  24
     A.18. Change from the regext 13 to regext 14 version  . . . . .  24
     A.19. Change from the regext 14 to regext 15 version  . . . . .  24
     A.20. Change from the regext 15 to regext 16 version  . . . . .  24
     A.21. Change from the regext 16 to regext 17 version  . . . . .  24
     A.22. Change from the regext 17 to regext 18 version  . . . . .  24
     A.23. Change from the regext 18 to regext 19 version  . . . . .  25
     A.24. Change from the regext 19 to regext 20 version  . . . . .  25
     A.25. Change from the regext 20 to regext 21 version  . . . . .  25
     A.26. Change from the regext 21 to regext 22 version  . . . . .  25
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  25

1.  Introduction

   The framework for internationalized email addresses is described in
   [RFC6530].  This document describes an Extensible Provisioning
   Protocol (EPP) [RFC5730] command-response extension that adds support
   for adding a second email address to the EPP contact object [RFC5733]
   mapping.  As described in [RFC5733], the email address associated
   with the base contact object MUST be an ASCII-only address.  The
   second email address can be either an ASCII-only email address or an
   internationalized, SMTPUTF8 [RFC6530] email address.  This second
   address can be used to identify an alternate ASCII-only email address
   for use in case of primary address delivery issues.  It can also be
   used to identify an SMTPUTF8 address for contact purposes, in which
   case the ASCII-only address can be used in case of SMTPUTF8 address
   delivery issues.

   While this extension adds support for an additional email address to
   contact objects, and that additional email address can be an SMTPUTF8
   address, it does not in any way update or change any other EPP
   extension that includes an email address.  Adding support for
   SMTPUTF8 addresses to those extensions will require an update to the
   relevant extension specifications.







Belyavskiy, et al.        Expires 3 April 2025                  [Page 3]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


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, "C:" represents lines sent by a protocol client and "S:"
   represents lines returned by a protocol server.  Indentation and
   white space in the examples are provided only to illustrate element
   relationships and are not REQUIRED in the protocol.

   The XML namespace prefix "addlEmail" is used for the namespace
   "urn:ietf:params:xml:ns:epp:addlEmail-1.0", but implementations MUST
   NOT depend on it and instead employ a proper namespace-aware XML
   parser and serializer to interpret and output the XML documents.

2.  Migrating to Newer Versions of This Extension

   Servers that implement this extension SHOULD provide a way for
   clients to progressively update their implementations when a new
   version of the extension is deployed.  A newer version of the
   extension is expected to use an XML namespace URI with a higher
   version number than earlier versions.

3.  Email Address Specification

   The EPP contact object mapping [RFC5733] normatively references
   [RFC5322] as the specification for email address syntax.  That
   specification does not include support for internationalized email
   addresses.  RFC 6530 [RFC6530] provides an overview and describes the
   framework for internationalized email.  SMTPUTF8 email address syntax
   is described in Section 3.3 of [RFC6531].  [RFC6531] extends the
   Mailbox, Local-part and Domain ABNF rules in [RFC5321] to support
   "UTF8-non-ascii", defined in Section 3.1 of [RFC6532], for the local-
   part and U-label, defined in Section 2.3.2.1 of [RFC5890], for the
   domain.  The validation rules described in RFC 6531 MUST be followed
   when processing internationalized email addresses associated with
   this extension.






Belyavskiy, et al.        Expires 3 April 2025                  [Page 4]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


4.  Additional Email Address Element

   A second email address can be set using the <addlEmail:addlEmail>
   element with the command and response extensions defined in
   Section 6.  The <addlEmail:addlEmail> element contains the following
   child element:

   <addlEmail:email>:  An element following the syntax in Section 3 for
       defining a second ASCII or SMTPUTF8 address.  An empty
       <addlEmail:email/> element unsets the second email address in the
       Update Command (Section 6.2.5) and indicates the second email is
       not set in the Info Response (Section 6.1.2).  The
       <addlEmail:email> element contains an OPTIONAL "primary"
       attribute that can be used to indicate that the extension email
       address should be treated as the primary email address for the
       extended contact object.  The "primary" attribute MUST NOT be
       present if the <addlEmail:email> is empty.

5.  Extension Considerations

5.1.  Signaling Client and Server Support

   The client and the server can signal support for the extension using
   a namespace URI in the login and greeting extension services
   respectively.  The namespace URI
   "urn:ietf:params:xml:ns:epp:addlEmail-1.0" is used to signal support
   for the extension.  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.

5.2.  Extension Behavior

5.2.1.  Extension Negotiated

   If both client and server have indicated support for SMTPUTF8
   addresses during session establishment, they MUST be able to process
   an SMTPUTF8 address in any extended contact object during the
   established EPP session.  Server and client obligations when this
   extension has been successfully negotiated in the EPP session are
   described below.

   The server MUST satisfy the following obligations when support for
   this extension has been negotiated:

   *  Accept SMTPUTF8 compliant addresses for the extended contact
      object in the EPP session.




Belyavskiy, et al.        Expires 3 April 2025                  [Page 5]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   *  Email address validation based on SMTPUTF8 validation rules
      defined in Section 3

   *  Storage of email properties that support internationalized
      characters.

   *  Return SMTPUTF8 compliant addresses for the extended contact
      object in EPP responses.

   *  Support the SMTP extension for internationalized email described
      in [RFC6531] when sending or receiving email.

   The client MUST satisfy the following obligations when support for
   this extension has been negotiated:

   *  Provide SMTPUTF8 compliant addresses for the extended contact
      object in the EPP session.

   *  Accept SMTPUTF8 compliant addresses for the extended contact
      object in EPP responses.

   *  Support the SMTP extension for internationalized email described
      in [RFC6531] when sending or receiving email.

5.2.2.  Extension Not Negotiated

   An extended contact object MUST NOT be provided or returned by either
   an EPP client or an EPP server when support for this extension is not
   successfully negotiated at the start of an EPP session.

6.  EPP Command Mapping

   A detailed description of the EPP syntax and semantics can be found
   in the EPP core protocol specification [RFC5730].  This section
   defines the provisioning of an alternate email address.

6.1.  EPP Query Commands

   EPP provides three commands to retrieve object information: <check>
   to determine if an object can be provisioned, <info> to retrieve
   information associated with an object, and <transfer> to retrieve
   object-transfer status information.

6.1.1.  EPP <check> Command

   This extension does not add any elements to the EPP <check> command
   or <check> response described in [RFC5730].




Belyavskiy, et al.        Expires 3 April 2025                  [Page 6]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


6.1.2.  EPP <info> Command

   This extension does not add any elements to the EPP <info> command
   response described in [RFC5730].

   If the query was successful, the server replies with an
   <addlEmail:addlEmail> element (Section 4) along with the regular EPP
   <resData>.

   The following is an example <info> contact response using the
   <addlEmail:addlEmail> extension with no alternate email address:

   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:      <contact:infData
   S:       xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   S:        <contact:id>sh8013</contact:id>
   S:        <contact:roid>SH8013-REP</contact:roid>
   S:        <contact:status s="linked"/>
   S:        <contact:status s="clientDeleteProhibited"/>
   S:        <contact:postalInfo type="int">
   S:          <contact:name>John Doe</contact:name>
   S:          <contact:org>Example Inc.</contact:org>
   S:          <contact:addr>
   S:            <contact:street>123 Example Dr.</contact:street>
   S:            <contact:street>Suite 100</contact:street>
   S:            <contact:city>Dulles</contact:city>
   S:            <contact:sp>VA</contact:sp>
   S:            <contact:pc>20166-6503</contact:pc>
   S:            <contact:cc>US</contact:cc>
   S:          </contact:addr>
   S:        </contact:postalInfo>
   S:        <contact:voice x="1234">+1.7035555555</contact:voice>
   S:        <contact:fax>+1.7035555556</contact:fax>
   S:        <contact:email>jdoe@example.com</contact:email>
   S:        <contact:clID>ClientY</contact:clID>
   S:        <contact:crID>ClientX</contact:crID>
   S:        <contact:crDate>1999-04-03T22:00:00.0Z</contact:crDate>
   S:        <contact:upID>ClientX</contact:upID>
   S:        <contact:upDate>1999-12-03T09:00:00.0Z</contact:upDate>
   S:        <contact:trDate>2000-04-08T09:00:00.0Z</contact:trDate>
   S:        <contact:authInfo>
   S:          <contact:pw>2fooBAR</contact:pw>



Belyavskiy, et al.        Expires 3 April 2025                  [Page 7]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   S:        </contact:authInfo>
   S:        <contact:disclose flag="0">
   S:          <contact:voice/>
   S:          <contact:email/>
   S:        </contact:disclose>
   S:      </contact:infData>
   S:    </resData>
   S:    <extension>
   S:      <addlEmail:addlEmail
   S:       xmlns:addlEmail="urn:ietf:params:xml:ns:epp:addlEmail-1.0">
   S:        <addlEmail:email/>
   S:      </addlEmail:addlEmail>
   S:    </extension>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

            Figure 1: Example <info> contact response using the
      <addlEmail:addlEmail> extension with no alternate email address

   The following is an example <info> contact response using the
   <addlEmail:addlEmail> extension with an ASCII alternate email
   address:

   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:      <contact:infData
   S:       xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   S:        <contact:id>sh8013</contact:id>
   S:        <contact:roid>SH8013-REP</contact:roid>
   S:        <contact:status s="linked"/>
   S:        <contact:status s="clientDeleteProhibited"/>
   S:        <contact:postalInfo type="int">
   S:          <contact:name>John Doe</contact:name>
   S:          <contact:org>Example Inc.</contact:org>
   S:          <contact:addr>
   S:            <contact:street>123 Example Dr.</contact:street>
   S:            <contact:street>Suite 100</contact:street>
   S:            <contact:city>Dulles</contact:city>
   S:            <contact:sp>VA</contact:sp>



Belyavskiy, et al.        Expires 3 April 2025                  [Page 8]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   S:            <contact:pc>20166-6503</contact:pc>
   S:            <contact:cc>US</contact:cc>
   S:          </contact:addr>
   S:        </contact:postalInfo>
   S:        <contact:voice x="1234">+1.7035555555</contact:voice>
   S:        <contact:fax>+1.7035555556</contact:fax>
   S:        <contact:email>jdoe@example.com</contact:email>
   S:        <contact:clID>ClientY</contact:clID>
   S:        <contact:crID>ClientX</contact:crID>
   S:        <contact:crDate>1999-04-03T22:00:00.0Z</contact:crDate>
   S:        <contact:upID>ClientX</contact:upID>
   S:        <contact:upDate>1999-12-03T09:00:00.0Z</contact:upDate>
   S:        <contact:trDate>2000-04-08T09:00:00.0Z</contact:trDate>
   S:        <contact:authInfo>
   S:          <contact:pw>2fooBAR</contact:pw>
   S:        </contact:authInfo>
   S:        <contact:disclose flag="0">
   S:          <contact:voice/>
   S:          <contact:email/>
   S:        </contact:disclose>
   S:      </contact:infData>
   S:    </resData>
   S:    <extension>
   S:      <addlEmail:addlEmail
   S:       xmlns:addlEmail="urn:ietf:params:xml:ns:epp:addlEmail-1.0">
   S:        <addlEmail:email>jdoe-alt@example.net</addlEmail:email>
   S:      </addlEmail:addlEmail>
   S:    </extension>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

            Figure 2: Example <info> contact response using the
       <addlEmail:addlEmail> extension with an ASCII alternate email
                                  address

   The following is an example <info> contact response using the
   <addlEmail:addlEmail> extension with an SMTPUTF8 primary email
   address:









Belyavskiy, et al.        Expires 3 April 2025                  [Page 9]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   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:      <contact:infData
   S:       xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   S:        <contact:id>sh8013</contact:id>
   S:        <contact:roid>SH8013-REP</contact:roid>
   S:        <contact:status s="linked"/>
   S:        <contact:status s="clientDeleteProhibited"/>
   S:        <contact:postalInfo type="int">
   S:          <contact:name>John Doe</contact:name>
   S:          <contact:org>Example Inc.</contact:org>
   S:          <contact:addr>
   S:            <contact:street>123 Example Dr.</contact:street>
   S:            <contact:street>Suite 100</contact:street>
   S:            <contact:city>Dulles</contact:city>
   S:            <contact:sp>VA</contact:sp>
   S:            <contact:pc>20166-6503</contact:pc>
   S:            <contact:cc>US</contact:cc>
   S:          </contact:addr>
   S:        </contact:postalInfo>
   S:        <contact:voice x="1234">+1.7035555555</contact:voice>
   S:        <contact:fax>+1.7035555556</contact:fax>
   S:        <contact:email>jdoe@example.com</contact:email>
   S:        <contact:clID>ClientY</contact:clID>
   S:        <contact:crID>ClientX</contact:crID>
   S:        <contact:crDate>1999-04-03T22:00:00.0Z</contact:crDate>
   S:        <contact:upID>ClientX</contact:upID>
   S:        <contact:upDate>1999-12-03T09:00:00.0Z</contact:upDate>
   S:        <contact:trDate>2000-04-08T09:00:00.0Z</contact:trDate>
   S:        <contact:authInfo>
   S:          <contact:pw>2fooBAR</contact:pw>
   S:        </contact:authInfo>
   S:        <contact:disclose flag="0">
   S:          <contact:voice/>
   S:          <contact:email/>
   S:        </contact:disclose>
   S:      </contact:infData>
   S:    </resData>
   S:    <extension>
   S:      <addlEmail:addlEmail
   S:       xmlns:addlEmail="urn:ietf:params:xml:ns:epp:addlEmail-1.0">
   S:        <addlEmail:email
               primary="true">麥克風@example.com</addlEmail:email>



Belyavskiy, et al.        Expires 3 April 2025                 [Page 10]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   S:      </addlEmail:addlEmail>
   S:    </extension>
   S:    <trID>
   S:      <clTRID>ABC-12345</clTRID>
   S:      <svTRID>54322-XYZ</svTRID>
   S:    </trID>
   S:  </response>
   S:</epp>

            Figure 3: Example <info> contact response using the
       <addlEmail:addlEmail> extension with an SMTPUTF8 primary email
                                  address

6.1.3.  EPP <transfer> Query Command

   This extension does not add any elements to the EPP <transfer> query
   command or <transfer> query response described in [RFC5730].

6.2.  EPP Transform Commands

   EPP provides five commands to transform objects: <create> to create
   an instance of an object, <delete> to delete an instance of an
   object, <renew> to extend the validity period of an object,
   <transfer> to manage object sponsorship changes, and <update> to
   change information associated with an object.

6.2.1.  EPP <create> Command

   This extension defines additional elements to extend the EPP <create>
   command of an object mapping like [RFC5733].

   The EPP <create> command provides a transform operation that allows a
   client to create an instance of an object.  In addition to the EPP
   command elements described in an object mapping like [RFC5733], the
   command MUST contain a child <addlEmail:addlEmail> element
   (Section 4) for the client to set an alternate email address.

   The following is an example <create> command to create a contact
   object with an alternate ASCII email address:












Belyavskiy, et al.        Expires 3 April 2025                 [Page 11]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   C:  <command>
   C:    <create>
   C:      <contact:create
   C:       xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   C:        <contact:id>sh8013</contact:id>
   C:        <contact:postalInfo type="int">
   C:          <contact:name>John Doe</contact:name>
   C:          <contact:org>Example Inc.</contact:org>
   C:          <contact:addr>
   C:            <contact:street>123 Example Dr.</contact:street>
   C:            <contact:street>Suite 100</contact:street>
   C:            <contact:city>Dulles</contact:city>
   C:            <contact:sp>VA</contact:sp>
   C:            <contact:pc>20166-6503</contact:pc>
   C:            <contact:cc>US</contact:cc>
   C:          </contact:addr>
   C:        </contact:postalInfo>
   C:        <contact:voice x="1234">+1.7035555555</contact:voice>
   C:        <contact:fax>+1.7035555556</contact:fax>
   C:        <contact:email>jdoe@example.com</contact:email>
   C:        <contact:authInfo>
   C:          <contact:pw>2fooBAR</contact:pw>
   C:        </contact:authInfo>
   C:        <contact:disclose flag="0">
   C:          <contact:voice/>
   C:          <contact:email/>
   C:        </contact:disclose>
   C:      </contact:create>
   C:    </create>
   C:    <extension>
   C:      <addlEmail:addlEmail
   C:       xmlns:addlEmail="urn:ietf:params:xml:ns:epp:addlEmail-1.0">
   C:        <addlEmail:email>jdoe-alt@example.net</addlEmail:email>
   C:      </addlEmail:addlEmail>
   C:    </extension>
   C:    <clTRID>ABC-12345</clTRID>
   C:  </command>
   C:</epp>

       Figure 4: Example <create> command to create a contact object
                   with an alternate ASCII email address

   The following is an example <create> command to create a contact
   object with a primary SMTPUTF8 email address:





Belyavskiy, et al.        Expires 3 April 2025                 [Page 12]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   C:  <command>
   C:    <create>
   C:      <contact:create
   C:       xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   C:        <contact:id>sh8013</contact:id>
   C:        <contact:postalInfo type="int">
   C:          <contact:name>John Doe</contact:name>
   C:          <contact:org>Example Inc.</contact:org>
   C:          <contact:addr>
   C:            <contact:street>123 Example Dr.</contact:street>
   C:            <contact:street>Suite 100</contact:street>
   C:            <contact:city>Dulles</contact:city>
   C:            <contact:sp>VA</contact:sp>
   C:            <contact:pc>20166-6503</contact:pc>
   C:            <contact:cc>US</contact:cc>
   C:          </contact:addr>
   C:        </contact:postalInfo>
   C:        <contact:voice x="1234">+1.7035555555</contact:voice>
   C:        <contact:fax>+1.7035555556</contact:fax>
   C:        <contact:email>jdoe@example.com</contact:email>
   C:        <contact:authInfo>
   C:          <contact:pw>2fooBAR</contact:pw>
   C:        </contact:authInfo>
   C:        <contact:disclose flag="0">
   C:          <contact:voice/>
   C:          <contact:email/>
   C:        </contact:disclose>
   C:      </contact:create>
   C:    </create>
   C:    <extension>
   C:      <addlEmail:addlEmail
   C:       xmlns:addlEmail="urn:ietf:params:xml:ns:epp:addlEmail-1.0">
   C:        <addlEmail:email
               primary="true">麥克風@example.com</addlEmail:email>
   C:      </addlEmail:addlEmail>
   C:    </extension>
   C:    <clTRID>ABC-12345</clTRID>
   C:  </command>
   C:</epp>

       Figure 5: Example <create> command to create a contact object
                   with a primary SMTPUTF8 email address

   This extension does not add any elements to the EPP <create> response
   described in [RFC5730].




Belyavskiy, et al.        Expires 3 April 2025                 [Page 13]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


6.2.2.  EPP <delete> Command

   This extension does not add any elements to the EPP <delete> command
   or <delete> response described in [RFC5730].

6.2.3.  EPP <renew> Command

   This extension does not add any elements to the EPP <renew> command
   or <renew> response described in [RFC5730].

6.2.4.  EPP <transfer> Command

   This extension does not add any elements to the EPP <transfer>
   command or <transfer> response described in [RFC5730].

6.2.5.  EPP <update> Command

   This extension defines additional elements to extend the EPP <update>
   command of an object mapping like [RFC5733].

   The EPP <update> command provides a transform operation that allows a
   client to update an instance of an object.  In addition to the EPP
   command elements described in an object mapping like [RFC5733], the
   command MUST contain a child <addlEmail:addlEmail> element
   (Section 4) for the client to be set or unset an alternate email.  If
   the alternate email does not apply to the object, the server MUST
   return an EPP error result code of 2201.

   The following is an example <update> command to set a contact object
   with an alternate ASCII email:





















Belyavskiy, et al.        Expires 3 April 2025                 [Page 14]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   C: <command>
   C:   <update>
   C:     <contact:update
   C:      xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   C:       <contact:id>sh8013</contact:id>
   C:     </contact:update>
   C:   </update>
   C:   <extension>
   C:     <addlEmail:addlEmail
   C:      xmlns:addlEmail="urn:ietf:params:xml:ns:epp:addlEmail-1.0">
   C:       <addlEmail:email>jdoe-alt@example.net</addlEmail:email>
   C:     </addlEmail:addlEmail>
   C:   </extension>
   C:   <clTRID>ABC-12345</clTRID>
   C: </command>
   C:</epp>

      Figure 6: Example <update> command to set a contact object with
                          an alternate ASCII email

   The following is an example <update> command to set a contact object
   with an alternate SMTPUTF8 email address:

   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   C: <command>
   C:   <update>
   C:     <contact:update
   C:      xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   C:       <contact:id>sh8013</contact:id>
   C:     </contact:update>
   C:   </update>
   C:   <extension>
   C:     <addlEmail:addlEmail
   C:      xmlns:addlEmail="urn:ietf:params:xml:ns:epp:addlEmail-1.0">
   C:       <addlEmail:email>麥克風@example.com</addlEmail:email>
   C:     </addlEmail:addlEmail>
   C:   </extension>
   C:   <clTRID>ABC-12345</clTRID>
   C: </command>
   C:</epp>

      Figure 7: Example <update> command to set a contact object with
                    an alternate SMTPUTF8 email address





Belyavskiy, et al.        Expires 3 April 2025                 [Page 15]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   The following is an example <update> command to unset a contact
   object alternate email address:

   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   C: <command>
   C:   <update>
   C:     <contact:update
   C:      xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
   C:       <contact:id>sh8013</contact:id>
   C:     </contact:update>
   C:   </update>
   C:   <extension>
   C:     <addlEmail:addlEmail
   C:      xmlns:addlEmail="urn:ietf:params:xml:ns:epp:addlEmail-1.0">
   C:       <addlEmail:email/>
   C:     </addlEmail:addlEmail>
   C:   </extension>
   C:   <clTRID>ABC-12345</clTRID>
   C: </command>
   C:</epp>

        Figure 8: Example <update> command to unset a contact object
                          alternate email address

   This extension does not add any elements to the EPP <create> response
   described in [RFC5730].

7.  Formal Syntax

   The EPP Additional Email Address Extension schema is presented here.

   The formal syntax shown here is a complete XML Schema representation
   of the object mapping suitable for automated validation of EPP XML
   instances.  The <CODE BEGINS> and <CODE ENDS> tags are not part of
   the XML Schema; they are used to note the beginning and ending of the
   XML Schema for URI registration purposes.

7.1.  EPP Additional Email Address Extension Schema












Belyavskiy, et al.        Expires 3 April 2025                 [Page 16]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   <CODE BEGINS>
   <?xml version="1.0" encoding="UTF-8"?>
   <schema xmlns="http://www.w3.org/2001/XMLSchema"
     xmlns:addlEmail="urn:ietf:params:xml:ns:epp:addlEmail-1.0"
     targetNamespace="urn:ietf:params:xml:ns:epp:addlEmail-1.0"
     elementFormDefault="qualified">
     <annotation>
       <documentation>Extensible Provisioning Protocol v1.0
          additional email address schema.</documentation>
     </annotation>
     <!-- Create, Update, and Info Response extension element -->
     <element name="addlEmail" type="addlEmail:addlEmailType" />
     <!--
       Single email element that can be empty
      -->
      <complexType name="addlEmailType">
        <sequence>
          <element name="email" type="addlEmail:emailType"/>
        </sequence>
      </complexType>
      <complexType name="emailType">
        <simpleContent>
          <extension base="token">
          <attribute name="primary" type="boolean" default="false"/>
         </extension>
       </simpleContent>
     </complexType>
     <!--
    End of schema.
    -->
   </schema>
   <CODE ENDS>

8.  IANA Considerations

8.1.  XML Namespace

   This document uses URNs to describe XML namespaces conforming to a
   registry mechanism described in RFC 3688 [RFC3688].  The following
   URI assignment should be made by IANA:

   Registration request for the addlEmail namespace:

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

   Registration request for the addlEmail XML Schema:



Belyavskiy, et al.        Expires 3 April 2025                 [Page 17]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   URI:  urn:ietf:params:xml:schema:epp:addlEmail-1.0
   Registrant Contact:  IESG
   XML:  See the "Formal Syntax" section of this document.

8.2.  EPP Extension Registry

   The EPP extension described in this document should be registered by
   IANA in the "Extensions for the Extensible Provisioning Protocol
   (EPP)" registry described in RFC 7451 [RFC7451].  The details of the
   registration are as follows:

   Name of Extension:  "Use of Internationalized Email Addresses in EPP
      protocol"
   Document status:  Standards Track
   Reference:  (This specification)
   Registrant Name and Email Address:  IESG, <iesg@ietf.org>
   Top-Level Domains(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
   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".






Belyavskiy, et al.        Expires 3 April 2025                 [Page 18]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


9.1.  Verisign EPP SDK

   Organization: Verisign Inc.

   Name: Verisign EPP SDK

   Description: The Verisign EPP SDK includes both a full client
   implementation and a full server stub implementation of draft-ietf-
   regext-epp-eai.

   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

10.  Security Considerations

   As is noted in Section 10.1 and Section 13 of [RFC6530],
   unconstrained Unicode in email addresses can introduce a class of
   security threats that do not exist with all-ASCII email addresses.
   As EPP exists in ecosystems where email addresses passed in EPP are
   displayed in RDAP and other services, and copy-and-paste of these
   email addresses is common for businesses transferring domains via
   EPP, there should be safeguards against these threats.  Therefore,
   use of the SMTPUTF8 email addresses as described in this document
   SHOULD be done with policies that disallow the use of unconstrained
   Unicode.  The domain-part of these SMTPUTF8 email addresses SHOULD
   conform to IDNA2008.  The local-part of these SMTPUTF8 email
   addresses SHOULD be restricted to Unicode that does not introduce the
   threats noted in [RFC6530].  One such possible solution would be to
   disallow characters outside of Unicode Annex 31
   (https://unicode.org/reports/tr31/).













Belyavskiy, et al.        Expires 3 April 2025                 [Page 19]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   As email address is often a primary end user contact, and an invalid
   email address may put communication with the end user at risk when
   such contact is necessary.  In case of an invalid domain name in the
   email address a malicious actor can register a valid domain name with
   similar U-label (homograph attack) and assume control over the domain
   name associated with the contact using social engineering techniques.
   To reduce the risk of the use of invalid domain names in email
   addresses, registries SHOULD validate the domain name syntax in
   provided email addresses and validate whether the domain name
   consists of the code points allowed by IDNA Rules and Derived
   Property Values (https://www.iana.org/assignments/idna-tables).

   Note that the syntax for internationalized email localparts is very
   liberal.  Domains are normalized during MX lookup, while localparts
   are unconstrained.  Implementers may wish to test that their database
   is able to store difficult localparts such as U+0061 U+0300 U+00E0.
   For more on normalization and these three code points, see [RFC5198]
   Section 3.

   In cases where a contact object contains two email addresses, be
   aware that either address may be forwarded to the other.  This
   implies that a message sent to an all-ASCII address may receive a
   reply from an SMTPUTF8 address, or vice versa.

11.  Acknowledgments

   The authors would like to thank Alexander Mayrhofer, Chris Lonvick,
   Gustavo Lozano, Jody Kolker, John C Klensin, John Levine, Klaus
   Malorny, Marc Blanchet, Marco Schrieck, Mario Loffredo, Murray S.
   Kucherawy, Patrick Mevzek, Pete Resnick, Takahiro Nemoto, Taras
   Heichenko, Arnt Gulbrandsen, and Thomas Corte for their careful
   review and valuable comments.

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>.






Belyavskiy, et al.        Expires 3 April 2025                 [Page 20]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   [RFC5321]  Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
              DOI 10.17487/RFC5321, October 2008,
              <https://www.rfc-editor.org/info/rfc5321>.

   [RFC5322]  Resnick, P., Ed., "Internet Message Format", RFC 5322,
              DOI 10.17487/RFC5322, October 2008,
              <https://www.rfc-editor.org/info/rfc5322>.

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

   [RFC5733]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)
              Contact Mapping", STD 69, RFC 5733, DOI 10.17487/RFC5733,
              August 2009, <https://www.rfc-editor.org/info/rfc5733>.

   [RFC5890]  Klensin, J., "Internationalized Domain Names for
              Applications (IDNA): Definitions and Document Framework",
              RFC 5890, DOI 10.17487/RFC5890, August 2010,
              <https://www.rfc-editor.org/info/rfc5890>.

   [RFC6530]  Klensin, J. and Y. Ko, "Overview and Framework for
              Internationalized Email", RFC 6530, DOI 10.17487/RFC6530,
              February 2012, <https://www.rfc-editor.org/info/rfc6530>.

   [RFC6531]  Yao, J. and W. Mao, "SMTP Extension for Internationalized
              Email", RFC 6531, DOI 10.17487/RFC6531, February 2012,
              <https://www.rfc-editor.org/info/rfc6531>.

   [RFC6532]  Yang, A., Steele, S., and N. Freed, "Internationalized
              Email Headers", RFC 6532, DOI 10.17487/RFC6532, February
              2012, <https://www.rfc-editor.org/info/rfc6532>.

   [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

   [RFC5198]  Klensin, J. and M. Padlipsky, "Unicode Format for Network
              Interchange", RFC 5198, DOI 10.17487/RFC5198, March 2008,
              <https://www.rfc-editor.org/info/rfc5198>.

   [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>.





Belyavskiy, et al.        Expires 3 April 2025                 [Page 21]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   [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>.

Appendix A.  Change History

A.1.  Change from 00 to 01

   1.  Changed from update of RFC 5733 to use the "Placeholder Text and
       a New Email Element" EPP Extension approach.

A.2.  Change from 01 to 02

   1.  Fixed the XML schema and the XML examples based on validating
       them.

   2.  Added James Gould as co-author.

   3.  Updated the language to apply to any EPP object mapping and to
       use the EPP contact mapping as an example.

   4.  Updated the structure of document to be consistent with the other
       Command-Response Extensions.

   5.  Replaced the use of "eppEAI" in the XML namespace and the XML
       namespace prefix with "eai".

   6.  Changed to use a pointed XML namespace with "0.2" instead of
       "1.0".

A.3.  Change from 02 to 03

   1.  The approach has changed to use the concept of Functional EPP
       Extension.

   2.  The examples are removed

A.4.  Change from 03 to 04

   1.  More detailed reference to email syntax is provided

   2.  The shortened eai namespace reference is removed

A.5.  Change from 04 to the regext 01 version

   1.  Provided the recommended placeholder value




Belyavskiy, et al.        Expires 3 April 2025                 [Page 22]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


A.6.  Change from the regext 01 to regext 02 version

   1.  Removed the concept of the placeholder value

A.7.  Change from the regext 02 to regext 03 version

   1.  Changed to use a pointed XML namespace with "0.3" instead of
       "0.2".

   2.  Some wording improvements

A.8.  Change from the regext 03 to regext 04 version

   1.  Some nitpicking

A.9.  Change from the regext 04 to regext 05 version

   1.  Some nitpicking

   2.  The "Implementation considerations" section is removed

A.10.  Change from the regext 05 to regext 06 version

   1.  Some nitpicking

A.11.  Change from the regext 06 to regext 07 version

   1.  Namespace version set to 1.0

A.12.  Change from the regext 07 to regext 08 version

   1.  Information about implementations is provided.

   2.  Acknowledgments section is added.

   3.  Reference to RFC 7451 is moved to Informative.

   4.  IPR information is provided

   5.  Sections are reordered to align with the other regext documents

A.13.  Change from the regext 08 to regext 09 version

   1.  Nitpicking according to Murray S.  Kucherawy review







Belyavskiy, et al.        Expires 3 April 2025                 [Page 23]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


A.14.  Change from the regext 09 to regext 10 version

   1.  Some nitpicking in the security considerations.

A.15.  Change from the regext 10 to regext 11 version

   1.  Nitpicking according mostly GenArt review.

A.16.  Change from the regext 11 to regext 12 version

   1.  XML schema registration request removed.

A.17.  Change from the regext 12 to regext 13 version

   1.  Document updated according to SecDir and ART-ART review.

A.18.  Change from the regext 13 to regext 14 version

   1.  Document updated according the IANA review #1231866.

A.19.  Change from the regext 14 to regext 15 version

   1.  Document updated according to ART-ART review.

A.20.  Change from the regext 15 to regext 16 version

   1.  Document removed the definition of the concept of a functional
       extension and updated to use a command-response extension, based
       on the feedback from John C Klensin.

   2.  Document removed the EAI abbreviation and uses SMTPUTF8 as
       umbrella term instead, based on the feedback from John C Klensin.

A.21.  Change from the regext 16 to regext 17 version

   1.  Added support for an alternate email during a transition period,
       based on feedback from John C Klensin.

A.22.  Change from the regext 17 to regext 18 version

   1.  Roll back to approach in -16 with the Cardinality of One Option,
       posted to and supported on the mailing list.

   2.  Replaced references of eai to smtputf8, based on feedback from
       John C Klensin.

   3.  Revised the Security Considerations section based on feedback and
       text from Andy Newton.



Belyavskiy, et al.        Expires 3 April 2025                 [Page 24]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


A.23.  Change from the regext 18 to regext 19 version

   1.  Reverted back to -17 with support for one or two email addresses
       using either ASCII or SMTPUTF8 and remove any reference to the
       requirement for an ASCII email address and remove the concept of
       a transition period.

A.24.  Change from the regext 19 to regext 20 version

   1.  Reverted Security Considerations section back to the content in
       -18 based on feedback from Andy Newton.

A.25.  Change from the regext 20 to regext 21 version

   1.  Added Scott Hollenbeck as a document editor.  Rewrote the draft
       to require ASCII-only email addresses in the base contact object
       mapping, allowing either ASCII-only or SMTPUTF8 addresses in the
       extension.

   2.  Replaced "eai" with "addlEmail" in the extension-identifying URNs
       and schema elements.

A.26.  Change from the regext 21 to regext 22 version

   1.  Fixed XML schema to use correct complexType.

   2.  Added Implementation Status section.

   3.  Example line formatting to fit within 72 characters.

Authors' Addresses

   Dmitry Belyavskiy
   8 marta st.
   Moscow
   127083
   Russian Federation
   Phone: +7 916 262 5593
   Email: beldmit@gmail.com


   James Gould
   VeriSign, Inc.
   12061 Bluemont Way
   Reston, VA 20190
   United States of America
   Email: jgould@verisign.com
   URI:   http://www.verisigninc.com



Belyavskiy, et al.        Expires 3 April 2025                 [Page 25]

Internet-Draft      Use of SMTPUTF8 Addresses in EPP      September 2024


   Scott Hollenbeck
   Verisign Labs
   12061 Bluemont Way
   Reston, VA 20190
   United States of America
   Email: shollenbeck@verisign.com
   URI:   https://www.verisignlabs.com/












































Belyavskiy, et al.        Expires 3 April 2025                 [Page 26]
