Hi guys, i have 2 windows domain, "mycompany.local" and "oa-mycompany.local" both for same organization. Now would know if possibile setup exchange server computer and join it to "mycompany.local" but configure the exchange mail server for use a "oa-mycompany.local" as LDAP for user directory and mailbox. It's possible to do it ? Thanks in advance.

Exchange server stores information on the configuration partition. that is common throught the forest. as far DSaccess is concerned it will try to select the domian controller in the same site in the same domain ans working DC and working Gc and config DC. you can tweak registery to staticaly define which domain controllers will be used. however not recomended as Dsaccess has in built failover mechanism if the curretly selected domain controller fails Dhruv

Yes, Exchange will use local domain DC and GC, Thats WHy MS recommend to have local DC GC must for exchange installation. you can promote other domain to use exchange domain resources, Mean mailbox can be created for other domain where you did not installed exchange. Please refer below KB's Deploy Exchange 2010 in an Exchange Resource Forest Topology http://technet.microsoft.com/en-us/library/aa998031.aspx Deploy Exchange 2010 in a Cross-Forest Topology http://technet.microsoft.com/en-us/library/aa998597.aspx Anil

Great! Thanks to all.