DDoS attack is the greatest threat of today in the field of Network Security. The ability to detect and prevent a network from DDoS attack and to ensure the high quality infrastructure is a back bone of today¿s network security issues. In this book, it has successfully validated an algorithm using OmNet++ Ver. 4.0 simulation to show how a DDoS attack can be detected and how the nodes can be protected from such an attack using GOSSIP protocol.