MIME Hierarchies of Body Parts

[This is preliminary documentation and subject to change.]

A MIME- message formatted body is divided into a hierarchy of nested body parts. The illustration below represents a typical MIME hierarchy for a message that contains the following content body parts:

• Alternative versions of the message, in US-ASCII plain text and HTML.
• A related image used to render the HTML content.
• A Microsoft Word attachment.

Body parts that hold content are displayed in a shaded box labeled "content." Multipart body parts act as structural nodes in the hierarchy and define the relationships of the content body parts.

Multipart/Mixed Structure

The format of a MIME header is specified by RFC 2045. For a complete description of the MIME message format, see RFC 2045, RFC 2046, RFC 2047, RFC 2048, and RFC 2049.