Summary: Ever expanding array of schemes for detection and prevention of Distributed Denial of Service (DDoS) attacks demands for a constant review and their categorization. As detection techniques have existed for a relatively longer period of time than defense mechanisms, researchers have categorized almost all the existing and expected forthcoming attacks. However, techniques for defense are still nurturing. Researchers have explored that there could be diverse ways of launching DDoS attacks. Consequently, need of defense strategy that adapts and responds autonomously to these variety of attacks is imperative. As more and more excavation is done in the arena of DDoS Defense Mechanisms, we understand that along with the conventional, well known DDoS Prevention and mitigation mechanism there are other factors that play equally important role in shielding a system from DDoS attacks. Deployment strategy, degree of cooperation of the internet host, code of behaviour while the system is already under attack, and post-attack analysis, etc, are such factors. In this paper, we have assorted the existing enormous defense mechanisms, and proposed an enhanced taxonomy that incorporates possible parameters that might influence DDoS Defense.