We are in the process of setting up a new internal domain and then we need to start testing the migration with moving users over with exchange.My question is do I need another Exchange server or can we still use the Exchange Server in the old Domain? The Old Domain name is the same as External and Internal and thats why we are moving away from that.Here is the Scanrio.2 way Transitive Trust Relationship is setup between DomainsOld Domain Class C Subnetcontoso.com[3] DC[2] Exchange 2007 ServerNew Domain Class B Subnetcnt.int[2] DCIf I don't need a new Exchange 2007 on cnt.int how can I move users over to the new AD and still have our Exchange Server on the old Domain handle the email?Thanks-F

Hi,Please ensure the two domains are in the same forest, then you need to run DomainPrep (Setup /DomainPrep) on the new Domain.Note: DomainPrep must run manually in any Domains which will not have Exchange server installed but which will contain Exchange recipients.After that, please use ADMT tool to migrate the user accounts from the old domain to the new domain.http://www.microsoft.com/downloads/details.aspx?FamilyID=6F86937B-533A-466D-A8E8-AFF85AD3D212&displaylang=enThanksAllen

So i guess I can use my Exchange 2007 server in my old Domain as a the primary Exchange Server for users in the new Domain?Thanks for your response.

Hi,Of course, you can do that. Exchange allows the resource and user account to be separated into different location.ThanksAllen