Cyber' terrorism has recently been said to be the biggest threat to our modern society. Every day a new cyber-scare story makes the headlines. The national government recognizes the importance of cyber security, as several officials have made clear in the past few years "Cyber security is among the most serious economic and national security challenges we will face in the 21st Century, we face a long-term challenge in cyberspace from foreign intelligence agencies and militaries, criminals, and others, and, this struggle will wreak serious damage on the economic health and national security. for the prevention and detection of cyber terrorism used intrusion detection system, intrusion detection system detect illegal behaviour of network over data. in current research trend performance of intrusion detection system is important issue. Now various authors' used machine learning and feature optimization technique for intrusion detection system. Machine learning technique is collection of all learning algorithm such as classification, clustering and regression. for the improvement of machine learning technique used feature optimization technique. In this paper presents review of intrusion detection technique using machine learning and feature optimization process.

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