Date Added: May 2012
One of the greatest threats that network security faces nowadays is Distributed Denial of Service attacks. A newer version of the Denial of Service attack, also called Distributed Denial of Service attack or DDoS. In a Distributed Denial-of-Service (DDoS) attack, an attacker may use one computer to attack another computer. An attacker may attempt to: "Flood" a network and thus reduce a legitimate user's bandwidth, prevent access to a service, or disrupt service to a specific system or a user. In this paper describe methods and techniques used in denial of service attacks. In this paper, simulate a distributed denial of service attack using ns-2 network simulator.