Research And Defense Stradegy Of DDoS

The rapid development of Internet brings tremendous impetus and impact to the entire community of science and technology, economy and culture. Internet also brings brand new feelings to people's life, work, learning and entertainment. People are increasingly dependent on the it, even inseparable to it. However, internet security was very fragile. Distributed denial of service attacks (DDoS) is one of the main threats of the network in recent years. Attackers invade Internet machines to collect vast network resources as zombies, and then generate attacks to main website or servers. DDoS has great destructive power, and is difficult to prevent.This article started with DoS attack, introduced early denial of service attack methods, principles and methods. Then we analyzed distributed denial of service (DDoS) attacks, from the invasion steps to the main attacking tools. So we realized the principle and harms of DDoS attacks.This paper introduced the defense mechanisms of DDoS mainly from four aspects as prevention, detection, tracking and mitigation. We found that we can fight against DDoS in many ways, but no one can prevent DDoS attacks completely. It requires Internet users, large networks and hosts and ISP's efforts to achieve network security. In the end of Chapter4, we gave some advices on small enterprise network.In Chapter 5, we presents a site-oriented DDoS defense mechanism, using Turing tests, SYN cookie to filter attacks, and then using some packet dropping strategy to increase server's availability. Finally, we made a number of recent issues, such as the Slashdot effect, Botnet, which produced new threats to the internet. We should concern with them.