Receivers Guidance for Implementing Branded Indicators for Message Identification (BIMI)
draft-brotman-ietf-bimi-guidance-01

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Network Working Group                                         A. Brotman
Internet-Draft                                              Comcast, Inc
Intended status: Best Current Practice                           T. Zink
Expires: February 6, 2020                      Zink Magical Contraptions
                                                          August 5, 2019

   Receivers Guidance for Implementing Branded Indicators for Message
                         Identification (BIMI)
                  draft-brotman-ietf-bimi-guidance-01

Abstract

   This document is meant to assist receivers or other mailbox providers
   by providing guidance to implementing Brand Indicators for Message
   Identification (BIMI).  This document is a companion to the main BIMI
   drafts which should first be consulted and reviewed.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 6, 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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   include Simplified BSD License text as described in Section 4.e of

Brotman & Zink          Expires February 6, 2020                [Page 1]
Internet-Draft                   BIMI-RG                     August 2019

   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Goals for BIMI  . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Should your site implement BIMI?  . . . . . . . . . . . . . .   3
     3.1.  If your site satisfies the requirements, this is likely a
           "yes".  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Site implementations  . . . . . . . . . . . . . . . . . . . .   4
   5.  Validation of a BIMI message  . . . . . . . . . . . . . . . .   4
     5.1.  BIMI Site Requirements  . . . . . . . . . . . . . . . . .   5
     5.2.  BIMI Certificate Validation . . . . . . . . . . . . . . .   6
   6.  Communicating BIMI results between the MTA and the MUA  . . .   6
     6.1.  Image Retrieval . . . . . . . . . . . . . . . . . . . . .   6
     6.2.  TTL of cached images  . . . . . . . . . . . . . . . . . .   7
     6.3.  Privacy Concerns  . . . . . . . . . . . . . . . . . . . .   7
     6.4.  Basic flow example  . . . . . . . . . . . . . . . . . . .   7
   7.  Domain Reputation . . . . . . . . . . . . . . . . . . . . . .   8
     7.1.  Rolling up based upon domain vs organizational domain . .   9
   8.  Working with MVAs . . . . . . . . . . . . . . . . . . . . . .  10
     8.1.  Resolving disputes  . . . . . . . . . . . . . . . . . . .  11
   9.  Troubleshooting BIMI  . . . . . . . . . . . . . . . . . . . .  11
   10. Public documentation  . . . . . . . . . . . . . . . . . . . .  12
     10.1.  For Brands:  . . . . . . . . . . . . . . . . . . . . . .  12
     10.2.  For users: . . . . . . . . . . . . . . . . . . . . . . .  12
   11. Appendix  . . . . . . . . . . . . . . . . . . . . . . . . . .  13
     11.1.  Glossary . . . . . . . . . . . . . . . . . . . . . . . .  13
   12. Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  14
   13. References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
   14. Normative References  . . . . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   The Brand Indicators for Message Identification (BIMI) specification
   introduces a method by which Mail User Agent (MUA, e.g, an email
   client) providers combine DMARC-based message authentication in
   addition to cryptographic methods to ensure the identity of a sender,
   and then to retrieve iconography that the sender has selected.  The
   iconography can then be displayed within the MUA.  The displayed
   iconography grants the sender brand impressions via the BIMI-capable