The threat of viruses, worms, information theft and lack of control of the IT infrastructure lead companies to implement security solutions to control the access to their internal IT networks. A new breed of software (Sygate, Vernier Networks, Microsoft, etc.) and hardware (Cisco) solutions from a variety of vendors has emerged recently. All are tasked with one goal controlling the access to a network using different methods and solutions. This presentation will examine the different strategies used to provide with network access controls. Flaws associated with each and every NAC solution presented would be presented. These flaws allow the complete bypass of each and every network access control mechanism currently offered on the market.