"IPS stands for Intrusion Prevention System. Intrusion means finding loopholes in the network and taking advantage of it. Intrusion is inappropriate, incorrect, or anomalous activity on host based or network-based systems. Malicious activity such as denial of service attacks, port-scans, or attempts to crack into computers are done by monitoring network traffic. Worms, Trojans, Spyware, Keyloggers, and other Malwares attacks. Intruders seek old, unpatched vulnerabilities as well as newly discovered vulnerabilities in Operating systems, Network services, and Protocols and take advantage of it.

Who Intrudes?
Someone outside trying to gain information. Disgruntled employee on the inside looking to cause a havoc. An intrusion prevention system is a computer security device that monitors network and/or system activities for malicious or unwanted behavior and can react, in real-time, to block or prevent those activities.

Role of IPS
An IPS system is a type of security management system that gathers and analyzes information and identifies possible security breaches. Security breaches include both Intrusions - attacks from outside the organization & Misuse - attacks from within the organization. It not only prevent but also detect the attack."