If you are configuring a primary domain controller, you must enter values in the Computer Name and Domain fields. If the domain you specify does not exist, it will be created, and this computer will be established as the PDC. If a domain by that name already exists, you must specify another domain name.

If you are configuring a backup domain controller, you will see four fields: Computer Name, Domain, Administrator Name, and Administrator Password. The administrator name and password you specify will be used to add this computer to the domain you specify, where it will be configured as a BDC. If the username and password you enter do not have administrator privileges in the domain, the computer cannot be added.

If you are configuring a standalone server, you will see four fields: Computer Name, Domain, Administrator Name, and Administrator Password. The administrator name and password you specify will be used to add this computer to the domain you specify, where it will be configured as a standalone server. If the user name and password you enter do not have administrator privileges in the domain, the computer cannot be added.

The figure below shows the window used to configure a primary domain controller (PDC).