Active Directory health checks: a practical operating routine

Active Directory health should be checked routinely, not only when users cannot sign in. A short, repeatable review catches replication, DNS, time, and capacity issues while they are still manageable. Begin with replication. Review domain-controller health, replication status, recent directory-service events, and the state of SYSVOL. Confirm that every domain controller uses the intended DNS configuration and that time synchronization follows the domain hierarchy. Kerberos depends on accurate time; a small drift can become a broad authentication problem. Then check the supporting evidence: free disk space, backup completion, monitoring alerts, failed scheduled tasks, and recent administrative changes. Record unusual findings and give each action an owner. The value of a health check is not the command output; it is the trend information and follow-through it creates.