Network Access Protection, or NAP, is a technology developed by Microsoft that was introduced in Windows Server 2008. It allows network and system administrators to define health parameters for computers connected to a network, and use those parameters to control network access. For example, if a computer is deemed "healthy," it would be allowed full access to the network. However, if the predetermined conditions are not met, network access may be limited or blocked altogether.
Administrators can use NAP to define health parameters, such as having the latest updates, updated antivirus definitions, or having a proper firewall installed and configured. NAP can help administrators better protect their company network from intrusions, virus infections, and other problems.