firewall

A logical or physical discontinuity in a network to prevent unauthorized access to data or resources.

A capability to limit network traffic between networks and/or information systems.

A system or combination of systems that enforces a boundary between two or more networks, typically forming a barrier between a secure and an open environment such as the Internet

Hardware and/or software gateway technology that protects network resources from unauthorized access. A firewall permits or denies computer traffic between networks with different security levels based upon a set of rules and other criteria.

A hardware or software link in a network that relays only data packets clearly intended and authorized to reach the other side.

A gateway that limits access between networks in accordance with local security policy.

A device or program that controls the flow of network traffic between networks or hosts that employ differing security postures.

the application of maximum thrust

a fireproof (or fire-resistant) wall designed to prevent the spread of fire through a building or a vehicle

(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