(computing) a security system consisting of a combination of hardware and software that limits the exposure of a computer or computer network to attack from crackers; commonly used on local area networks that are connected to the internet.
3.
A fireproof (or fire-resistant) wall designed to prevent the spread of fire through a building or a vehicle.
... boxes that led through the antechamber from the control console to the reactor beyond the firewall. Everything looked fine. That meant that whatever it was that had fouled up the controls was on the other side of ... — The Bramble Bush • Gordon Randall Garrett
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