Microsoft Network Policy and Access Services (Microsoft NPAS) is a server role in Windows Server 2008 and Windows Server 2012 that allows administrators to provide local and remote network access. It also allows admininistrators to define and enforce policies for network access authentication, authorization and client health.
The NPAS server role includes Network Policy Server (NPS), Health Registration Authority (HRA), Routing and Remote Access Service (RRAS) and Host Credentials Authorization Protocol (HCAP). In Windows Server 2008, NPAS can be used to deploy virtual private networking (VPN), dial-up networking and 802.11-protected wireless access. In Windows Server 2012, NPAS can be used to configure Network Access Protection (NAP), secure wired and wireless access points, and Remote Authentication Dial-In User Service (RADIUS) servers and proxies.