Is is possible to run a report to export the LegacyExchangDN attribute of Mailboxes in the Exchange Organization.
The LegacyExchangeDN attribute of of Mailboxes is stored in the "Mailbox DN" field of the MessageStats Database. This has been carried over in MessageStats from Exchange 5.5.
The "Mailbox DN" field can be added to the "Inventory | Mailboxes" report
The Inventory report will now display the LegacyExchangDN attribute under the column heading "Mailbox DN"