RFC 2049 (rfc2049) - Page 2 of 24


Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and Examples



Alternative Format: Original Text Document



RFC 2049                    MIME Conformance               November 1996


   ASCII text data in Internet mail header fields. The fourth document,
   RFC 2048, specifies various IANA registration procedures for MIME-
   related facilities. This fifth and final document describes MIME
   conformance criteria as well as providing some illustrative examples
   of MIME message formats, acknowledgements, and the bibliography.

   These documents are revisions of RFCs 1521, 1522, and 1590, which
   themselves were revisions of RFCs 1341 and 1342.  Appendix B of this
   document describes differences and changes from previous versions.

Table of Contents

   1. Introduction ..........................................    2
   2. MIME Conformance ......................................    2
   3. Guidelines for Sending Email Data .....................    6
   4. Canonical Encoding Model ..............................    9
   5. Summary ...............................................   12
   6. Security Considerations ...............................   12
   7. Authors' Addresses ....................................   12
   8. Acknowledgements ......................................   13
   A. A Complex Multipart Example ...........................   15
   B. Changes from RFC 1521, 1522, and 1590 .................   16
   C. References ............................................   20

1.  Introduction

   The first and second documents in this set define MIME header fields
   and the initial set of MIME media types.  The third document
   describes extensions to RFC 822 formats to allow for character sets
   other than US-ASCII.  This document describes what portions  of MIME
   must be supported by a conformant MIME implementation. It also
   describes various pitfalls of contemporary messaging systems as well
   as the canonical encoding model MIME is based on.

2.  MIME Conformance

   The mechanisms described in these documents are open-ended.  It is
   definitely not expected that all implementations will support all
   available media types, nor that they will all share the same
   extensions.  In order to promote interoperability, however, it is
   useful to define the concept of "MIME-conformance" to define a
   certain level of implementation that allows the useful interworking
   of messages with content that differs from US-ASCII text.  In this
   section, we specify the requirements for such conformance.







Freed & Borenstein          Standards Track