We have two organisations that currently reside within a single Windows 2003 AD Forest in two seperate domains. Within Domain A there is a Exchange 2007 server and within Domain B there is an Exchange 2003 server. These servers reside within the same Exchange organisation in two sites and are linked via a routing group connector. Each server has seperate site specific SMTP connectors to Mimecast and handle there own email. All PC's are using Outlook 2003 for connectivity. As there is a single server for each company these servers are gateways and mailbox / PF servers.
The companies are splitting so we have had to build a new Windows 2008 AD forest. Within this forest is a new Windows 2008 and Exchange organisation on an Exchange 2007 server. We have to move all of the users and mailboxes from Domain B into the new forest. Once the migration of all systems are complete the links between the companies will be broken and the existing forest cleaned up. However this clean up wont happen until several weeks after the Exchange migration has happened
I have tested the use of the Ex2007 move-mailbox cmdlet and will be using this to migrate the mailboxes to the new server / Org. I was planning on doing an Outlook Public folder export / import via a PST file to handle the public folder user data. However I have concerns about some of the system PF's specifically the Free / Busy information. I cannot see how to migrate this information and I'm not sure what the impact will be for the users. Can you explain?
I also have a question with regards to message routing. Once the mailboxes are moved into the new Forest staff in Domain A will still need to email people in the new forest. However as the old server from Domain B will still remain in the short term how do i stop Domain A's server trying to send messages to Domain B instead of the new server in the new Forest? What is the easiest / best method of overcoming this issue. Do I just have to have to uninstall Exchange from Dmain B or is it as simple as removing the routing group connector, changing the authorative domains for the organisation or something else.....