— An Intrusion Detection System is an application used for monitoring the network and protecting it from the intruder. Intrusion is a set of actions aimed to compromise these security goals. IDS have the computer security goals which are important for the data mining for extraction of data like confidentiality, integrity, and availability. This research study the performance measures of IDS is important for the security purposes. KDD 99 has 41 features. The IDS approached is used with the help of neural network technique of data mining and the Genetic algorithm is used as a classifier. The all features of KDD99 are used in this study. In this research, the feature is selected and extracted instead of using all features. The feature selection is done with the help of Correlation and feature extraction is done with the help of KPCA. The selection of features is according to the Eigen values of the features. The neural network is used for the change the weightage of the error. The neural network is basically runs many times and change weightage according to this.