Details

Microsoft Exchange has built-in functionality for journaling, which takes a copy of all email messages and places the copies into a mailbox that has been designated as a journaling mailbox. When email messages are copied to the journaling mailbox, they are copied in a proprietary format and cannot be changed easily. The copy is identical to your original email - including the content of the message, the sender and recipient, and any attachments. This includes embedded images and even your signature and disclaimer so you can be confident that the message you see in Exclaimer Mail Archiver is identical to the message sent to the recipient.
Exclaimer Mail Archiver draws upon this functionality to provide a robust, easily accessible archive of all messages (or defined subsections of email). An Exclaimer Mail Archiver service polls any defined Exchange journaling mailboxes continuously, extracts (i.e. removes) messages and pushes them through the Exclaimer rules engine to determine if and then where they should be archived.

Exclaimer Mail Archiver by default creates a Journaling Rule that takes all messages that are routed through your Microsoft Exchange environment and puts them in a Journal mailbox of your choice. However, in environments that have multiple Exchange Mailbox Databases you can choose to target a specific Mailbox Database.
Mail Archiver FAQ