This is a guide for transitioning Exchange 2003 to 2010 in the same domain.

n.b (An Exchange migration is from one Active Directory forest to a different Active Directory forest.)

1. Bring the Exchange organization to Exchange Native Mode.
2. Upgrade all Exchange 2003 Servers to Exchange Server 2003 Service Pack 2.
3. Bring the AD forest and domains to Windows Server 2003 Functional (or higher) levels.
4. Upgrade at least one Global Catalog domain controller in each AD Site that will house Exchange Server to Windows Server 2003 SP2 or greater.
5. Run ServerManagerCmd -i NET-Framework from 2008 R2 server.
6. (only run if setup is not run by Schema, Enterprise and Domain Admin)Prepare a Windows Server 2008 (RTM or R2) x64 edition server for the first Exchange 2010 server.
7. Install the AD LDIFDE tools on the new Exchange 2010 server (to upgrade the schema). ServerManagerCmd -i RSAT-ADDS
8. Install Web Server role on the CAS server and any necessary prerequisites. (If additional Exchange servers are on the network)
9. Set the Net.Tcp Port Sharing service to automatic
10. Install the Office 2007 converter filter Pack http://go.microsoft.com/fwlink/?LinkId=123380
11. Run setup on the Exchange 2010 server, upgrade the schema, and prepare the forest and domains. (Setup runs all in one step or separate at the command line.)
12. Install CAS server role servers and configure per 2010 design. (If required)
13. Install Mailbox servers and configure Databases (DAG if needed)
14. Install Hub Transport role and configure per 2010 design.
15. Create public folder replicas on Exchange 2010 servers using shell. Run cd <Exchange Installation Path>\Scripts then run.\AddReplicatoPFRecursive.ps1 -TopPublicFolder \ -ServerToAdd Servername in Exchange Shell, or Exchange 2010 Public Folder tool.
16. Transfer inbound and outbound mail traffic to the HT servers.
17. Rehome the Offline Address Book (OAB) generation server to Exchange Server 2010.
18. Transfer OWA, ActiveSync, and Outlook Anywhere traffic to new CAS servers.
19. Move mailboxes to Exchange Server 2010 using Move Mailbox Wizard or Powershell.

    Indivdual users:New-MoveRequest -Identity “someuser@corp.local” -DomainController DC02 -TargetDatabase “Mailbox Database 01″

    Entire mailboxes: .\MoveMailbox.ps1 -MailboxDatabase “SRV-01\First Storage Group\Mailbox Store (SRV-01)” -TargetDatabase “Mailbox Database” (note: ps1 scripts must be run from \Exchsvr\Scripts location in Management Shell)

20. Run Get-MoveRequest –MoveStatus Completed | Remove-MoveRequest to remove Move requests otherwise mailboxes can’t be moved again.
21. Update Email address policy to Exchange 2010

    Get-EmailAddressPolicy | where {$_.RecipientFilterType –eq “Legacy”} | Set-EmailAddressPolicy –IncludedRecipients AllRecipients

22. Update Address Lists

Set-AddressList “All Users” -IncludedRecipients MailboxUsers

Set-AddressList “All Groups” -IncludedRecipients MailGroups

Set-AddressList “All Contacts” -IncludedRecipients MailContacts

Set-AddressList “Public Folders” -RecipientFilter { RecipientType -eq ‘PublicFolder’ }

Set-GlobalAddressList “Default Global Address List” -RecipientFilter {(Alias -ne $null -and (ObjectClass -eq ‘user’ -or ObjectClass -eq ‘contact’ -or ObjectClass -eq ‘msExchSystemMailbox’ -or ObjectClass -eq ‘msExchDynamicDistributionList’ -or ObjectClass -eq ‘group’ -or ObjectClass -eq ‘publicFolder’))}

1. Rehome Public Folder Hierarchy on new Exchange Server 2010 Admin Group.
2. Transfer all Public Folder Replicas to Exchange Server 2010 Public folder store(s).
3. Delete Public and Private Information Stores from Exchange 2003 server(s).
4. Delete Routing Group Connectors to Exchange Server 2003.

   Get-RoutingGroupConnector | Remove-RoutingGroupConnector

5. Delete Recipient Update Service agreements using ADSIEdit

   “CN=Recipient Update Services,CN=Address Lists Container,CN=Commonname, CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=domain,DC=local”

6. Uninstall all Exchange 2003 servers through add/remove programs