Domain controller


A domain controller is a server computer that responds to security authentication requests within a computer network domain. It is a server on a network that is responsible for allowing host access to domain resources. It authenticates users, stores user account information and enforces security policy for a domain. It is most commonly implemented in Microsoft Windows environments, where it is the centerpiece of the Windows Active Directory service. However, non-Windows domain controllers can be established via identity management software such as Samba and Red Hat FreeIPA.

Software

The software and operating system used to run a domain controller usually consists of several key components shared across platforms. This includes the operating system, an LDAP service, a network time service, and a computer network authentication protocol service and Domain Name System may also be included on the same server or on another domain-joined server.

Implementation

Domain controllers are typically deployed as a cluster to ensure high-availability and maximize reliability. In a Windows environment, one domain controller services as the Primary Domain Controller and all other servers promoted to domain controller status in the domain server as a Backup Domain Controller. In Unix-based environments, one machine serves as the master domain controller and others serve as replica domain controllers, periodically replicating database information from the main domain controller and storing it in a read-only format.