The IT/OT boundary is the interface where information technology systems, such as servers, cloud platforms, and business networks, meet operational technology that controls or monitors physical processes, such as power equipment, industrial controllers, or building systems. It matters because the two environments have different goals: IT prioritizes data, uptime, and access, while OT prioritizes safety, stability, and deterministic control.
In cyber security, this boundary is important because weaknesses can cross from digital actions into physical effects. An attacker may not need to compromise a PLC or breaker directly if they can influence workloads, scheduling, telemetry, or control signals that affect power demand. Defenders therefore watch not only for malware and unauthorized access, but also for load spikes, timing changes, and other operational side effects. Protecting the IT/OT boundary usually means segmentation, strict access control, monitoring of transient behavior, and coordination between security teams and engineers.