RFC 1343 (rfc1343) - Page 1 of 10
A User Agent Configuration Mechanism for Multimedia Mail Format Information
Alternative Format: Original Text Document
Network Working Group N. Borenstein, Bellcore
Request for Comments: 1343 June 1992
A User Agent Configuration Mechanism
For Multimedia Mail Format Information
Status of This Memo
This is an informational memo for the Internet community,
and requests discussion and suggestions for improvements.
This memo does not specify an Internet standard.
Distribution of this memo is unlimited.
Abstract
This memo suggests a file format to be used to inform
multiple mail reading user agent programs about the
locally-installed facilities for handling mail in various
formats. The mechanism is explicitly designed to work with
mail systems based Internet mail as defined by RFC's 821,
822, 934, 1049, 1113, and the Multipurpose Internet Mail
Extensions, known as MIME. However, with some extensions it
could probably be made to work for X.400-based mail systems
as well. The format and mechanism are proposed in a manner
that is generally operating-system independent. However,
certain implementation details will inevitably reflect
operating system differences, some of which will have to be
handled in a uniform manner for each operating system. This
memo makes such situations explicit, and, in an appendix,
suggests a standard behavior under the UNIX operating
system.
Introduction
The electronic mail world is in the midst of a transition
from single-part text-only mail to multi-part, multi-media
mail. In support of this transition, various extensions to
RFC 821 and RFC 822 have been proposed and/or adopted,
notably including MIME [RFC-1341]. Various parties have
demonstrated extremely high-functionality multimedia mail,
but the problem of mail interchange between different user
agents has been severe. In general, only text messages have
been shared between user agents that were not explicitly
designed to work together. This limitation is not
compatible with a smooth transition to a multi-media mail
world.
One approach to this transition is to modify diverse sets of
mail reading user agents so that, when they need to display
mail of an unfamiliar (non-text) type, they consult an
external file for information on how to display that file.
That file might say, for example, that if the content-type
Borenstein