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Versions: 00

Network Working Group                                           P. Jones
Internet-Draft                                              G. Salgueiro
Intended status: Standards Track                                   Cisco
Expires: January 9, 2020                                    July 8, 2019


                WebFinger Email Automatic Configuration
               draft-jones-webfinger-email-autoconfig-00

Abstract

   This document describes procedures for automatically configuring an
   email client by using WebFinger to convey mail server configuration
   and security-related information.

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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   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 January 9, 2020.

Copyright Notice

   Copyright (c) 2019 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
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.





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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   2
   3.  Example User Scenario . . . . . . . . . . . . . . . . . . . .   3
   4.  Email Auto-Configuration Procedures . . . . . . . . . . . . .   5
     4.1.  Initiating a WebFinger Query  . . . . . . . . . . . . . .   5
     4.2.  Processing the JSON Resource Descriptor . . . . . . . . .   5
     4.3.  Requesting the Email Configuration Document . . . . . . .   5
   5.  Email Configuration Document Syntax . . . . . . . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   6
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   6
     9.3.  URIs  . . . . . . . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   Configuring email clients manually can be a time-consuming and
   mundane task that can actually be fairly arduous as the number of
   users or clients increases.  While people with technical
   understanding of the various protocols and settings employed can
   configure a single email client fairly easily, the task can prove
   challenging and frustrating for non-technical users.

   This document defines procedures utilizing WebFinger [RFC7033] that
   make it trivial for end-users to configure email clients with little
   or no assistance and with minimal technical skill.  All that is
   required for the user to do is enter his or her account identifier,
   select an email account, and provide credentials.

   Following these procedures, the complexity of configuring an email
   client is shifted away from the end-user and pushed onto the software
   tools that implement these procedures and the email administrators
   who would have to configure the settings for each user server-side
   and publish the required configuration data.  However, the
   configuration data can be generated with automated tools, meaning
   there would be minimal effort for the email administrators.

2.  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




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   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  Example User Scenario

   To illustrate how the procedures work, assume Alice just got a new
   computer and installed her favorite email client.  She is using
   services from Example Mail Corporation and she was told her account
   identifier is "alice@mail.example" and her password is "abc123".  She
   actually has two different accounts with Example Mail Corporation,
   one for personal use and one for her business.  The accounts are
   aptly named "Personal" and "Business".

   When Alice starts her email client and adds a new email account, the
   client will ask her for her account identifier.  She will then enter
   "alice@mail.example", at which point the client will initiate a
   WebFinger query to the host "mail.example".  That HTTP [RFC7230]
   query will look something like this:

     GET /.well-known/webfinger?resource=acct%3Aalice%40mail.example \
         HTTP/1.1
     Host: mail.example

   (The backslash character '\' is there only to indicate the following
   line is part of the same line.)

   As per the WebFinger specification, a JSON Resource Descriptor (JRD)
   will be returned with a number of different entires.  For brevity,
   the following reply shown excludes most of the content that is not
   applicable to this example.  The reply might look like this:





















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   HTTP/1.1 200 OK
   Access-Control-Allow-Origin: *
   Content-Type: application/jrd+json

   {
     "subject" : "acct:alice@mail.example",
     "links" :
     [
       {
         "rel" : "email-autoconfig",
         "href" : "https://mail-config.mail.example/alice.personal.json"
         "titles" :
         {
           "en-us" : "Personal"
         }
       },
       {
         "rel" : "email-autoconfig",
         "href" : "https://mail-config.mail.example/alice.business.json"
         "titles" :
         {
           "en-us" : "Business"
         },
       }
     ]
   }

   Noting there are two "email-autoconfig" entries in the response, one
   named "Personal" and one named "Business", Alice's email client will
   prompt her to select one of the email accounts to configure to
   provide a password.  She selects the one named "Personal", at which
   point the email client will issue a subsequent HTTP query to the URI
   associated with that account:

      GET /alice.personal.json HTTP/1.1
     Host: mail-config.mail.example

   The server "mail-config.mail.example" might require her to
   authenticate using the password for her email account, which is why
   she was prompted for it when selecting the account.  Once the email
   client satisfies whatever authentication challenge it is presented,
   the server will then respond with a JSON document that contains all
   of the configuration information necessary for the email client to
   self-provision her "Personal" account.  That reply might look
   something like this:






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     HTTP/1.1 200 OK
     Access-Control-Allow-Origin: *
     Content-Type: application/jrd+json

     {
       "address" : "alice.i.wonder@mail.example",
       "smtp" :
       {
         "login" : "alice.i.wonder",
         "host" : "outbound.mail.example",
         "port" : 587,
         "login-required" : true,
         "transport" : "starttls"
       },
       "imap" :
       {
         "login" : "alice.i.wonder",
         "host" : "imap.mail.example",
         "port" : 143,
         "transport" : "starttls"
       }
     }

   The email client would utilize this information to configure itself
   to access the mail server using SMTP and IMAP.  The email client
   would reasonably assume that the account password provided is the
   same password used with both of those protocols.  While that might
   not be correct, it certainly simplifies the user's life if it is the
   same.  However, authentication may be via a digital certificate, for
   example, conveyed in this response document.

4.  Email Auto-Configuration Procedures

   TBD

4.1.  Initiating a WebFinger Query

   TBD

4.2.  Processing the JSON Resource Descriptor

   TBD

4.3.  Requesting the Email Configuration Document

   TBD





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5.  Email Configuration Document Syntax

   TBD

6.  Security Considerations

   TBD

7.  IANA Considerations

   TBD

   We will need to register "email-autoconfig" in the Link Relations
   registry: https://www.iana.org/assignments/link-relations/link-
   relations.xhtml [1]

8.  Acknowledgments

   TBD

9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC7033]  Jones, P., Salgueiro, G., Jones, M., and J. Smarr,
              "WebFinger", RFC 7033, DOI 10.17487/RFC7033, September
              2013, <https://www.rfc-editor.org/info/rfc7033>.

   [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>.

9.2.  Informative References

   [RFC7230]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Message Syntax and Routing",
              RFC 7230, DOI 10.17487/RFC7230, June 2014,
              <https://www.rfc-editor.org/info/rfc7230>.








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9.3.  URIs

   [1] https://www.iana.org/assignments/link-relations/link-
       relations.xhtml

Authors' Addresses

   Paul E. Jones
   Cisco
   7025 Kit Creek Rd.
   Research Triangle Park, North Carolina  27709
   USA

   Phone: +1 919 476 2048
   Email: paulej@packetizer.com


   Gonzalo Salgueiro
   Cisco
   7025 Kit Creek Rd.
   Research Triangle Park, North Carolina  27709
   USA

   Phone: +1 919 392 3266
   Email: gsalguei@cisco.com


























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