The enumeration indicates the direction in which a message is coming or going.
Assembly: Microsoft.Exchange.Data.Transport (in Microsoft.Exchange.Data.Transport.dll)
|The direction of the message cannot be determined.|
|For an incoming message, the message comes from the pickup directory, the replay directory, a Delivery Status Notification (DSN), or the mail submission API. For an outgoing message, the message is going to a server that is not a Simple Mail Transfer Protocol (SMTP) server or it is an application message on the destination server.|
|The message is coming from or going to a mailbox.|
|The message is coming from or going to an SMTP endpoint.|
|The message is coming from a Delivery Agent.|