Question like this has been asked on technet and all over the web, however I've yet to see a question that is specific to my scenario.

I have one forest with two domains and one exchange server instance. We divulged part of the company and as such we had to create a new domain namespace for this new company. Since the both companies are strapped for cash getting another exchange server is not an option in the foreseeable future.

Forest F1

Domain A - Original domain, Server 2008R2, Exchange 2010SP1, Lync

Domain B - New domain, Server 2012, No exchange. New users were created in domain b and mailboxes were created for users using EMC in domain A

Scenario 1 - I've tried using the various combinations of  Prepare-MoveRequest.ps1, ADMT, and New-MoveRequest once it worked but I inadvertently created a new account instead of migrating a user. The documentation accompanying these scripts seem to assume two forest and two separate exchange instances.

eg : http://blogs.technet.com/b/meamcs/archive/2011/06/10/exchange-2010-cross-forest-migration-step-by-step-guide-part-i.aspx

Scenario 2- Since most of the documentation assumes either Cross forest migration or an Exchange instance in both domains/forest. I was wondering if its possible to do the following;

- Disable user1mailbox from user1 in forest A (creating a disconnected mailbox)

- Migrate user1 to forest B using ADMT

- Reconnect user1mailbox to user1 in forest B

We must be able to provide all the exchange features OWA..etc also I must be able move these mailboxes to a new exchange server instance in domain b if needed.

If scenario 1 is the recommended way to do this I probably need to do some more reading. However it just seems for my particular scenario it seems logical to disconnect/reconnect mailboxes.

Hi ,

1.If you would like to have the new namespace for the users in domain B then you need to have the new email address policy created on the exchange server in domain A and also you need to add the new namespace as the accepted domain domain in the exchange in domain A.Then the new email address policy can be filtered and applied based upon the OU in the domain B or else by using the custom based attributes for the user accounts in domain B.

Same time you could need to have the new namespace registered externally and also you would need to create the MX records for the receiving emails from internet to the email addresses which ends with the new namespace in exchange server in domain A .

As an additional info don't forget to have the PTR records for the new domain.

2.In case if you would like to move all the user accounts from domain A to domain B then you would have to do an intra forest migration by using the ADMT .

Note :

In a single forest there is no need to do an cross forest migration or inter forest migration.

Intra forest migration is fully supported for single active directory forest.