1. A network security system for examining and processing a a user request for an inner data system, said network security system comprising: a reaction system; an examination module for receiving the user request and determining whether the user request satisfies a predetermined safety condition for producing a examination result; and a redirect system for receiving the examination result, wherein the redirect system transmits the user request to the inner data system if the examination result shows the safety condition is satisfied, and the redirect system transmits the user request to the reaction system and the reaction system provides response contents according to the user request with a predetermined response method if the examination result shows the user request fails to satisfy the safety condition, and wherein the response contents has a same format as a response result of the inner data system if the user request is transmitted to the inner data system.