Final answer:
Active Directory is the directory service used with Windows domains, providing a central database for network, user, and computer authentication and authorization.
Step-by-step explanation:
The directory service used with Windows domains is Active Directory (AD). Active Directory is a directory service developed by Microsoft for Windows domain networks. It is included in most Windows Server operating systems as a set of processes and services. An AD domain controller authenticates and authorizes all users and computers in a Windows domain type network—assigning and enforcing security policies for all computers and installing or updating software. AD stores information and settings in a central database. Active Directory services use Lightweight Directory Access Protocol (LDAP) for accessing and maintaining distributed directory information services over an Internet Protocol (IP) network.