Hi, I had installed windows 2000 Domain controller in my office, and i installed one more additional domain controller for my branch office, these two domain controllers are in Different site connected by wan link. all my 5 FSMO operation roles are in First Domain controller in my main office. Now my question is 1)If PDC role goes down in my domain controller , whether my users will abel to log on to the domain, by refering additional domain controller. 2) If my main DC itself down is there any possibilities, user in my branch office can log on to the domain, becuase i had installed additional domain controller in that site (branch office). pls tell us what i need to do if any one of the problem occurs.

In a w2k AD there is no PDC! One of the FSMOroles is PDC-emulation which means the DC emulates a PDC for the remaing NT4 BDC:s. Once you get rid of the NT4 BDC:s (and workstations) you set the AD to native mode. For logon authentication the global catalog is used. The GC can, and should, run on all your DC:s. So, answer to your questions: yes. And no. As long as the WAN is up there is no problem. If the WAN link is down they will only be able to log on to computers they have been authenticated on before if they are on the site with the "dead" DC.