In the Distributed Denial of Service (DDoS) defense research, rate-limiting methods have been proposed to alleviate the damage of attacks according to different congestion control mechanisms. This paper presents a new game-theoretical methodology to evaluate effectiveness of typical DDoS defense mechanisms quantitatively. A complete strategic game model is constituted for DDoS attack and defense warfare. Besides simulation studies, mixed strategic Nash Equilibrium is computed to analysis and predict DDoS warfare behaviors in the end of the paper. In this model, the comparing performances of congestion control mechanisms such as Aggregated-based Congestion Contro l(ACC) and Pushback are denoted by the results of utility function. At last, probabilistic results are given to conclude and interpret the using and availability of this methodology.Seventh International Conference on Networking 978-0-7695-3106-9/08 $25.00