Wi-Fi has been widely deployed in enterprise and campus networks. With this wide deployment, it becomes increasingly important to understand the behavior of Wi-Fi interference and automatically managed Wi-Fi to ensure their normal operation and security. Selfish Carrier Monitoring (SCM) approach is used to detect a selfish attack of a Wi-Fi network by sniffer monitoring. Wi-Fi performance is analyzed by sniffers that capture transmitted frames. Multiple sniffers are deployed to monitor the selfish carrier sense behavior by initiating the threshold value with. Multiple sniffers in large areas, some areas are covered with more than one sniffer, and neighbour sniffers will observe the information about coverage areas. A node can be selfish by raising the Clear Channel Assessment (CCA) threshold value. Based on the identifications any misbehavior in carrier sense behavior with in the node pairs, and the selfish attack by tuning the threshold value are found. By detecting attacker nodes in the network, and sniffer broadcasting the information to the neighbour, in an isolate the attacker and choose alternate path for broadcasting. Distributed sniffers efficiently detect and isolate attacker in routing path. Selfish attack activates the sniffer monitoring system even when the network is in active state or inactive state depending on the suspicious value. Obtaining more accurate additional coverage area ratio of sensing neighbour coverage knowledge will also minimize router overhead.