With the increase of wireless LAN usage in homes and enterprises due to its numerous benefits, authenticating the ever increasing number of devices and their users has become a challenge to proprietors of such kind networks. A MAC address, a physical network address that is used as basis for this study, has a copy of its value in the system software that can be spoofed and altered rendering the address not unique, not secure and unreliable. On the contrary, a computers serial number is hard-coded in the system hardware only and therefore cannot be spoofed and altered making it unique, secure and reliable. The research, therefore, was aimed at designing a model that demonstrates how a computers serial number can be used for authenticating a computer in a wireless local area network. In order to achieve the research objective, the study examined the inbuilt access and use of a computers serial number prototype model as an alternative method of authenticating devices in a network. Design science research methodology that involved design and development, demonstration and model evaluation was employed. A Serial Number Based Authentication Prototype or SNAP was therefore designed using state chart and flow chart diagrams based on dynamic programming, developed over evolutionary prototyping and test run on a static experimental design using Java Development Kit and MySQL platforms to demonstrate, as proof of concept, that a computers serial number can be used to authenticate a computer in a wireless local area network. From the test runs whose outcomes were the binary values yes or no, it was found out that SNAP can actually allow or deny, enable or disable a computer in a network based on the computers serial number. The researcher therefore, recommends that the prototype be scaled up, then adopted as a network device authentication method.