A gateway’s primary task is to transfer messages. Microsoft Exchange Server delivers outgoing messages to a gateway by attaching them to a special message called a message transfer envelope (MTE), and delivering them to the gateway’s MTS-OUT folder. The gateway must take the messages from the MTS-OUT folder and deliver them to the foreign system. For incoming messages, the gateway must use the information in an incoming message to create a MAPI message, which it must put in its MTS-IN folder.
The MTE provides a list of recipients to whom the gateway must deliver the message. The message is treated as an attached message object within the MTE. Your gateway must be able to process MTE information and deliver the attached messages, and also transfer several types of reports that inform message originators and recipients about message status.