The movement from wired network to wireless network has been a trend in the past few years. Comparing to other wireless networks MANET is important one. MANET contains the collection of mobile nodes or computers with a wireless transmitter and receiver that communicate with each other. MANET is a self-configurable and has automatic IP configuration features with several independent nodes. Due to this MANETS are used in applications like military and in natural disasters. Security measures play an important role in all these applications. Hence it is necessary to include intrusion-detection system for MANETs.