After you establish the root domain, you can create additional domains within the tree if your network plan requires multiple domains. Each new domain within the tree will be a child domain of the root domain, or a child domain of another child domain.

For example, you create a domain named europe.contoso.com, which is a child domain of the root domain, contoso.com. The next domain that you create within that tree can be a child of constoso.com or a child of europe.contoso.com.

To create a child domain, run Dcpromo.exe to start the Active Directory Installation wizard. Complete the wizard by using the information in the following table.

On this wizard page Do this
Domain Controller Type Click Domain controller for a new domain.
Create Tree or Child Domain Click Create a new child domain in an existing domain tree.
Network Credentials Specify the user name, password, and domain name of a user account in the Enterprise Admins group, which exists in the root domain of the forest.
Child Domain Installation Specify the DNS name of the parent domain, and the name of the new child domain.
Domain NetBIOS Name Specify the NetBIOS name for the new domain.
Database and Log Locations Specify locations for the Active Directory database and log files.
Shared System Volume Specify the location for the shared system volume.
Windows NT 4.0 RAS Servers Specify whether to weaken permissions to support users who access the network through remote access servers running Windows NT 4.0.

After you finish specifying the installation information, the Active Directory Installation wizard installs Active Directory, converts the computer to a domain controller, and adds the Active Directory consoles to the Administrative Tools menu on that computer.