As the network based computer system plays an important role in modern society they have become target of enemies and criminals. Therefore the authors need to find the best possible ways to protect the peoples' IT System. Different methods and algorithms are developed and proposed in recent years to improve intrusion detection systems. The most important issue in current systems is false positive alarm rate. This is because current systems are poor at detecting novel anomaly attacks. These kinds of attacks refer to any action that significantly deviates from the normal behavior which is considered intrusion.