Domain controller

A domain controller (DC) refers to a server responsible for managing security authentication requests within a computer network domain. It facilitates user access to domain resources by verifying identities, maintaining account data, and applying the domain's security policy. While domain controllers are predominantly utilized in Microsoft Windows environments through the Windows Active Directory framework, alternative solutions exist for non-Windows systems, such as identity management platforms like Samba and Red Hat FreeIPA.

Software

The software powering domain controllers generally comprises an operating system—most commonly Windows Server or Linux—alongside an LDAP service (for example, Red Hat Directory Server), a network time synchronization service (ntpd, chrony), and an authentication mechanism such as Kerberos. Additional elements might include a public key infrastructure component (like Active Directory Certificate Services or DogTag) and a Domain Name System service (Windows DNS or BIND), which can be hosted on the same server or distributed across multiple domain-joined machines.

Implementation

To achieve high availability and robustness, domain controllers are frequently deployed in groups. Within Windows environments, one domain controller functions as the Primary Domain Controller (PDC), while others operate as Backup Domain Controllers (BDC). In Unix-based configurations, a single master domain controller is designated, supported by replica controllers that periodically synchronize and maintain read-only copies of the database.

See also

• Apple Open Directory
• Domain controller (Windows)
• Microsoft Windows Active Directory
• Red Hat Identity Manager / Red Hat FreeIPA