Each network domain must have a controlling element unless it is a peer-to-peer system. Networks share resources, and require controllers for printing, routing, email, faxing and file sharing. There are two types of domain controllers, the Primary Domain Controller (PDC) and the Backup Domain Controller (BDC).

  • Primary Domain Controller
    The is one Primary Domain Controller in a domain. The PDC must be running Windows NT Server OS. This server maintains the central database for all account information and all security policies.

  • Backup Domain Controller
    Other servers in the domain can be Backup Domain Controllers. There can be more than one BDC in a domain. The job of the BDC is to maintain a copy of the PDC database. It can assist in authenticating users on the system. If the PDC should go offline or crash, the BDC can be promoted to PDC status.


    To set up a server to be a domain controller, you must select the option when installing the operating system. If the option was not installed, you must re-install the operating system to allow the server to become a domain controller. If a server does not have the domain controller option, it cannot be promoted to the PDC or BDC.

  • Log in or registerto write something here or to contact authors.