Which of the following is an example of a directory service?

• A. Active Directory Domain Services
• B. DNS
• C. DHCP
• D. LDAP

Answer: (A)

Directory services are centralized systems that store information about network resources and the users who access them, along with the attributes of those resources, and provide mechanisms for searching, authentication, authorization, and policy enforcement. Active Directory Domain Services is an example because it acts as such a repository for Windows identities and resources—storing user accounts, groups, computer objects, and policy data, and enabling logon and access control within a domain. LDAP is the access protocol used to interact with directory services, allowing clients to query and update the directory. DNS and DHCP perform other network functions: DNS translates hostnames to IP addresses, while DHCP assigns IP configuration to devices. So the directory service example is Active Directory Domain Services.