Exchange 2010 cross forest migration while keeping user accounts in the source domain

Hi Experts,

I've a requirement to migrate Exchange mailboxes into a completely new AD forest and then link them to existing AD forest user accounts. Current environment is as follows,

Domain: abc.local
DC : Windows 2008
Exchange : Exchange 2010

Target Forest :
Domain : xyz.local
DC : Windows 2008
Exchange : Exchange 2010

Current Exchange domain accepting (Authoritative) for mail domain. Source domain (abc.local) is the only forest open to internet and accepting mails. What we need to do is create mailbox in the xyz.local side and migrate the mailboxes. Customer doesn't like to migrate the user account but only to map a mailbox in xyz.local

My main concern is mail are accepted by abc.local so how we can configure that Exchange server to replay mail to xyz.local server when we migrate several user mailboxes. Hope someone can shed some light over here.
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MichaelVHConnect With a Mentor Commented:
Hi there,

what you are trying to do is actually create a so-called "resource forest".

There are some pretty good tutorials/guides on that available with a lot of valuable information:

What is basically comes to is this (high-level):
1. You deploy Exchange 2010 in a new forest (your resource forest)
2. You create 'linked' users in the resource forest (linked to an account in the user account forest)
3. In order to be able to route email during migration, Exchange has to be set up to support 'namespace sharing'. To do this, you'll find some information about it here:
4. You move mailboxes.

If you've got any questions left, please don't hesitate to ask!


ksksilvaAuthor Commented:
Hi Experts,

Anyone has carried out similar project like this? All I want to know is how can we have the same e-mail domain named mailboxes co-exist between two active directory forest during the mailbox mapping and mailbox integration to the target forest.

ksksilvaAuthor Commented:
Hi Experts,

The requirement has been change now. Please have a look at the new attachment. Actually now my client require cross forest migration scenario but the user account won't move across the forest.

Refer below links for cross forest migration :

Deploy Exchange 2010 in a Cross-Forest Topology :

Configure Cross-Forest Connectors :

Hope this helps.

Glen KnightCommented:
This question has been classified as abandoned and is being closed as part of the Cleanup Program. See my comment at the end of the question for more details.
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