MANET has exceptional individuality like changing topology, reduced bandwidth, wireless radio medium, limited resource and no centralized control. It is composed of mobile nodes which traverse through wireless link by agreeing to route message for each other. Securing ad hoc routing is a great challenge. The mobile ad hoc network is subjected to various types of attack at different layers of the protocol stack. In this proposed work, our focus is on the attack on the network layer. DOS (Denial of Service) attack affects the network performance by causing data loss. Many solutions have been proposed to encounter DOS, but the issues still persist because it is not prevented or avoided completely. We propose a solution for DOS in MANET using AODV without affecting the network performance.