RackGuardian protects rack-mounted systems, including SCADA, Building Automation Systems (BAS), and Industrial Control Systems (ICS), from cyber threats through a data-diode architecture that prevents inbound connections, creating a stealth shield around connected devices to block cyber attacks. The system offers secure remote management capabilities, allowing users to perform diagnostics and issue commands remotely as if locally present. It features end-to-end data encryption, self-learning analytics that monitor for statistical anomalies, and compliance with ISA/ANSI 18.2 alarm management standards. It provides an intuitive web dashboard for monitoring and responding to threats, ensuring protection of OT systems in mission-critical infrastructure.