A protocol bridge is a component that translates or relays traffic between different industrial communication protocols. In operational technology, it may connect older field devices to modern supervisory software, or link vendor tools, web interfaces, and remote monitoring platforms. By making mismatched systems work together, it improves interoperability and simplifies management.
In cyber security, the downside is that every bridge expands the trust boundary. It can expose devices that were never meant to be directly reachable and may convert a single compromise into access across multiple layers of a control network. Attackers can abuse a bridge to issue unauthorized commands, alter setpoints, suppress alarms, or pivot between IT and OT environments. Defenders should inventory bridges, restrict who can use them, segment networks carefully, and monitor for unusual protocol translations or unexpected control changes.