MIME (Multipurpose Internet Mail Extensions): Mechanisms for Specifying and Describing the Format of Internet Message Bodies (RFC1341)
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2019-Feb-11
Internet Society Requests For Comment (RFCs)
N. Borenstein: AUTHOR [+1]
This document redefines the format of message bodies to allow multi-part textual and non-textual message bodies to be represented and exchanged without loss of information. [STANDARDS-TRACK]
Network Working Group N. Borenstein, Bellcore Request for Comments: 1341 N. Freed, Innosoft June 1992
MIME (Multipurpose Internet Mail Extensions):
Mechanisms for Specifying and Describing the Format of Internet Message Bodies
Status of this Memo
This RFC specifies an IAB standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "IAB Official Protocol Standards" for the standardization state and status of this protocol. Distribution of this memo is unlimited.
RFC 822 defines a message representation protocol which specifies considerable detail about message headers, but which leaves the message content, or message body, as flat ASCII text. This document redefines the format of message bodies to allow multi-part textual and non-textual message bodies to be represented and exchanged without loss of information. This is based on earlier work documented in RFC 934 and RFC 1049, but extends and revises that work. Because RFC 822 said so little about message bodies, this document is largely orthogonal to (rather than a revision of) RFC 822.
In particular, this document is designed to provide facilities to include multiple objects in a single message, to represent body text in character sets other than US- ASCII, to represent formatted multi-font text messages, to represent non-textual material such as images and audio fragments, and generally to facilitate later extensions defining new types of Internet mail for use by cooperating mail agents.
This document does NOT extend Internet mail header fields to permit anything other than US-ASCII text data. It is recognized that such extensions are necessary, and they are the subject of a companion document [RFC -1342].
A table of contents appears at the end of this document.
Borenstein & Freed [Page i]
Since its publication in 1982, RFC 822 [RFC-822] has defined the standard format of textual mail messages on the Internet. Its success has been such that the RFC 822 format has been adopted, wholly or partially, well beyond the confines of the Internet and the Internet SMTP transport defined by RFC 821 [RFC-821]. As the format has seen wider use, a number of limitations have proven increasingly restrictive for the user community.
RFC 822 was intended to specify a format for text messages. As such, non-text messages, such as multimedia messages that might include audio or images, are simply not mentioned. Even in the case of text, however, RFC 822 is inadequate for the needs of mail users whose languages require the use of character sets richer than US ASCII [US-ASCII]. Since RFC 822 does not specify mechanisms for mail containing audio, video, Asian language text, or even text in most European languages, additional specifications are needed
One of the notable limitations of RFC 821/822 based mail systems is the fact that they limit the contents of electronic mail messages to relatively sho...