Figure 302: MIME Multipart Message Structure

A MIME multipart message consists of a set of main headers and a main body portion, like all messages. Within the main body are one or more body parts, each of which has its own body-part-specific headers followed by the body part itself; each body part is shown in blue. The Content-Type header of the message as a whole (highlighted in green) indicates that the message type is multipart, and the boundary parameter specifies the name of the delimiter, in this case just called “Delimiter” (how boring.) This delimiter is used to separate the body parts from each other and from the preamble and epilogue that begin and end the message body, respectively.