What is the function of Domain Controller 1 (DC01)?

• A. An authentication server that maintains a duplicate copy of user and computer databases for the domain
• B. A DNS server
• C. A DHCP server
• D. A mail server

Answer: (A)

The key function of a Domain Controller is to authenticate users and computers for the domain by hosting the Active Directory directory and enforcing security policies. It stores an authoritative copy of the domain’s user and computer accounts and replicates changes to other domain controllers, so logon requests and resource access are validated consistently across the domain. When someone signs in or tries to access domain resources, the DC verifies credentials (often issuing Kerberos tickets) and applies the appropriate policies. That description matches the intended role of DC01 as the authentication server maintaining the domain’s directory.

While a DNS server, a DHCP server, and a mail server perform important network functions, they are separate roles. A Domain Controller may also run DNS to support domain operations, but the defining function described here is authentication and directory management.