Date Added: May 2012
Distributed Denial of Service (DDOS) attacks are one of the most widely spread problems faced by most of the Internet Service Providers (ISP's) today. Mitigation of these attacks has gained utmost importance in the present scenario. A number of mitigation techniques have been proposed by various researchers. The authors enable one to distinguish between legitimate and illegitimate traffic and accordingly either drops or detects the unwanted packets. Thus enabling us to mitigate the impact of these attacks on the servers. This paper focusing on Distributed Denial of Service attack, surveys, classifies and also systematically analyzes the various proposed mitigation techniques during the last decades by the researchers.