LAB5: Promoting a BDC to PDC
In this exercise, we are going to assume that we need to take the PDC down for maintenance. If we did not promote a BDC to take over the domain, we could not make any changes to the accounts database till the PDC was restored.

Users would still be able to logon to the domain, because a BDC is capable of authenticating user logon requests.

We are assuming that you have the PDC and BDC running. Ensure this is the case before continuing.

1. Start Server Manager at the PDC

   Start->Programs->Administrative Tools->Server Manager

   

2. Highlight the entry for the BDC and choose
   Computer->Promote to Primary Domain Controller

   

3. Click Yes to the dialog box, so that the BDC can be promoted.
4. Once the promotion has taken place, which may take a couple of minutes, refresh the server manager screen [F5].

   What computer is now the PDC? ...........................................

   What computer is now the BDC? ...........................................

5. Promote the current BDC to a PDC [this will restore the original PDC]

Summary
If the PDC for the domain goes off-line, users will still be able to logon to the domain if there is a BDC available. However, if there is no PDC, no changes to the domain accounts database is possible till the PDC is restored.