Windows firewall rules disappearance traced to management policies

A recent systems administration discussion highlighted servers losing all Windows Firewall rules, causing network outages. The issue was later identified as being caused by new Microsoft Defender for Endpoint policies. Administrators can diagnose the problem by checking rule counts, examining Windows event logs for deletion events, and identifying the modifying application and user account. Comparing affected servers with working ones helps determine if the cause is centralized policy or local changes.