Hardware or software product that gathers and analyzes information from various areas within a computer or a network to identify possible security breaches, which include both intrusions (attacks from outside the organizations) and misuse (attacks from within the organizations.) It’s important to note the IDS only “detects” malicious activity – it does not block this activity. An Intrusion Prevention System (which most likely is the same device but just in a different mode of operation ) “prevents or blocks” the malicious activity. (see below).

Intrusion Detection System