Associating File Name Extensions with MIME

Internet message formats are used when messages are sent to or received from an Internet client. When a user sends mail from a MAPI client, such as Microsoft Outlook®, to an Internet client, such as Outlook Express, SMTP converts the message from Microsoft rich text format (RTF) to MIME. The file name extensions that you define for each MIME type enable clients to recognize mail attachments and open them. By default, several content types are associated with file name extensions. Generally, the default associations are sufficient for content conversion. For detailed instructions on manage associations for file name extensions, see How to Manage Associations for File Name Extensions.