If you are migrating users in batches from Exchange 2003, it is important to set up mail forwarding for users already migrated to the new Destination when the MX records still point to the Source environment.
The Visual Basic (VB) script in the hyperlink below discovers all mailboxes within the Source domain and creates contact forwards for each one within a contact forwards Organizational Unit (OU). Note: The forward itself on the mailbox is not set. This only creates forwarding objects for coexistence.
- Download the VB script: New-Exchange2003ContactForwards.zip.
- Modify script file and change the forwarding domain name.
- Launch a command prompt.
- Run the script on a computer that is joined to the domain in which you wish to discover.
- Run the script on a computer in each domain that contains mailboxes.
This script will create contact forwards within a top-level OU of the referenced domain.