I have two separate forests A and B trusting each other. Exchange 2007 is setup on forest A and users from forest B have their mailbox on this Exchange server as well using linked mailbox. I just want to know that if some how domain B is down, anyway to let users from this domain to keep logon their mailbox? Any caching mechanism in place?

On Wed, 2 May 2012 01:28:37 +0000, BDP Kenneth wrote: >I have two separate forests A and B trusting each other. > >Exchange 2007 is setup on forest A and users from forest B have their mailbox on this Exchange server as well using linked mailbox. > >I just want to know that if some how domain B is down, anyway to let users from this domain to keep logon their mailbox? Any caching mechanism in place? No. But you can certainly add another DC/GC to the domain. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

Just one more question. At the time create a new Linked Mailbox, there is an option called "Linked domain controller". Is this entry matters during future logins? I tried your suggestions, there is two DC in the said trusted domains, and both are global catalogs. Nevertheless, user cannot login their mailbox when one of the DC is down. The offline DC is the one I input in the "Linked domain controller" field earlier.

On Fri, 4 May 2012 08:50:27 +0000, BDP Kenneth wrote: >Just one more question. At the time create a new Linked Mailbox, there is an option called "Linked domain controller". Is this entry matters during future logins? No. It's used only during the creation of the linked mailbox. >I tried your suggestions, there is two DC in the said trusted domains, and both are global catalogs. Nevertheless, user cannot login their mailbox when one of the DC is down. The offline DC is the one I input in the "Linked domain controller" field earlier. Which one of those two DCs holds the PDC FSMO role? Is it the one that's down? If you transfer the PDC role to the other DC before taking the other one down do you still have the problem? Do you have the necessary info in your DNS to contact both of those DCs in the other forest? This is really an Active Directory or DNS issue, I think. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP