Security is one of the most important problems to be considered in the Wireless Local Area Networks (WLANs). Several security techniques were initiated to solve the available security bugs. In this paper, they propose to design a detection and defense mechanism against DDoS attacks. Initially GIDA module is deployed, so that DDoS attack is detected using the game theory decision model in the Access Point (AP). A Master Session Key (MSK) is calculated and a hash function is created for security. For the authentication and association of frames a client puzzle based defense mechanism is used in the AP.