Now-a-days, there is drastic dependency on the internet in every sector like private, government etc. For protecting these networks from attacks is very crucial task. A single intrusion in a computer network can lead to loss of data or unauthorized use or modification of personal data. There are many methods and algorithm to detect attacks, most of the methods detects attacks and categorized it in two groups, normal or intrusion. A new approach to Intrusion Detection (ID) is based on Artificial Neural Network (ANN).