Envelope Message

The journal messages that are sent to the journaling mailboxes are MAPI messages (the body of which is the original message sent by the sender). These MAPI messages contain the journaling property, which also contains all the recipient information for the message. The journaling mailbox requests that the Exchange Store service package an envelope message that contains all this data. The resulting message is similar to a non-delivery report (NDR) message. The body contains Exchange-generated data (in this case the sender, the original message ID, and a list of recipients), and the original message is attached.

Sample journal message

Until the journal message is created by the Exchange server that hosts the journal recipient mailbox, envelope data is attached as a property to the message instead of copied as embedded content. Attaching the envelope data as a property is done so that existing mailbox servers do not have to manage the additional transaction volume that the Exchange Store service creates when constructing journal reports locally at the point of data gathering. Instead, the mailbox servers that host the journal mailboxes assume the responsibility for constructing journal reports at delivery time.