Unidirectional Gateway (Data Diode)
Industrial/ICS 🏭 • Network Security 🌐
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Difficulty: premium
Definition
A unidirectional gateway (data diode) is a hardware-enforced, one-way data transfer device that allows information to flow out of a protected OT network without permitting any inbound traffic back in.
Examples
- A refinery pushes historian data from OT Level 3 to an IDMZ/IT reporting server through a data diode; no IT system can send commands back toward controllers.
- A utility exports syslog and security events from substation OT to a central SOC via a diode, preserving monitoring while blocking remote access paths.
Discover 🔎
Unidirectional gateways create a physical, one-way boundary so plants can share necessary data (trends, events, KPIs) without creating control paths back into real-time systems. Unlike firewalls, which are software-configured to block traffic, a diode enforces direction in hardware, eliminating whole classes of misconfiguration and remote-control risk.
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