intrusion detection system

A process or subsystem, implemented in software or hardware, that automates the tasks of (a) monitoring events that occur in a computer network and (b) analyzing them for signs of security problems. [SP31] (See: intrusion detection.)

A security alarm system to detect unauthorized entry. [DC6/9].

Tutorial: Active intrusion detection processes can be either host- based or network-based:

• "Host-based": Intrusion detection components -- traffic sensors and analyzers -- run directly on the hosts that they are intended to protect.
• "Network-based": Sensors are placed on subnetwork components, and analysis components run either on subnetwork components or hosts.