Mitigating dynamic DoS attacks in mobile ad hoc network

Mobile ad hoc networks operate without any fixed infrastructure and centralized administration. It is an autonomous system of wirelessly connected mobile nodes having the capability to operate as host and router as well. The dynamic nature of ad hoc network increases the topology designing challenges. Security is an important and essential requirement in Mobile Ad-hoc Networks (MANET). MANETs are more vulnerable to security attacks as compared to wired networks due to lack of a centralized authority, dynamic network topology, easy eavesdropping and low bandwidth. Although many types of security attacks have been studied in MANETs, like black hole attack, wormhole attack, jellyfish attack, Denial of service attack, rushing attack, sinkhole attack, Dynamic denial of service attack, but the most pioneered attack is a dynamic denial of services attack (dDoS) because of their potential impact. In dDoS attack, the malicious node continuously sends RREQ to victim node and makes it as busy as possible. So, that node cannot process the legitimate RREQ coming from another node. So, here we have proposed one solution against dDoS attack. The proposed method uses packet delivery ratio, number of route request per unit time to find whether this node is malicious one or not. If the node is found malicious one then node manager will inform to all other node in transmission range.