Hi, We have two seperate forests: Forest 1: AD 2008, Exchange 2010 Sp1 Forest 2: AD 2003, No Exchange rite now Now, we want to use the Exchange multi-tenant support of exchange 2010 of forest1 to give mailbox to the users of forest2. Is it possible ? i am confused becuz i read at technet article at the following link: http://technet.microsoft.com/en-us/library/ff923267.aspx#establish Multi-tenant support in Exchange 2010 Service Pack 1 (SP1) is supported only for a single domain forest. The following configurations aren’t supported: Resource forest Parent-child domains Discontiguous namespace Disjoint namespace I am not sure that this statement is giving answer of my question or not. Please help Ali Salman Naqvi.

Now, we want to use the Exchange multi-tenant support of exchange 2010 of forest1 to give mailbox to the users of forest2. Is it possible ? You need resource forest, bot multi-tenant. Forest 1 with Exchange 2010 will host mailboxes for users in forest 2. See the below for more info. http://technet.microsoft.com/en-us/library/aa998031.aspx

Hi, You can create a mailbox for the user in forest2 without Exchange multi-tenant. You already have the resource forest which hosting your exchange server and the account forest which contain the user objects. To create a mailbox for the external user in the account forest, please refer the following steps: A. Create a trust between these two forest. B. Then you will be able to create a mailbox and then link it to the user in the account forest: 1. Open EMC, expand to Recipient Configuration, right click Mailbox and choose "New mailbox". 2. Select Linked mailbox, click next. Select New user click next. 3. Enter the user information then click next. 4. Enter the mailbox settings, click next. 5. Under "Trusted forest or domain", click Browse, select your account forest. You must create the trust between these two forest. 6. Check the box "Use the following windows user account to access linked domain controller." 7. Type in the administrator account of the account domain. 8. Under linked domain controller, click Browse, then select the DC in the account forest. 9. Under linked master account, click Browse, select the master account in the account forest. More information: Deploy Exchange 2010 in an Exchange Resource Forest Topology http://technet.microsoft.com/en-us/library/aa998031.aspx

Hi, Is there any update?