Network Policy and Access Services (NPAS) is a component of Windows Server 2008. It replaces the Internet Authentication Service (IAS) from Windows Server 2003. NPAS helps you safeguard the health and security of a network. The NPAS server role includes Network Policy Server (NPS), Health Registration Authority (HRA), and Host Credential Authorization Protocol (HCAP). In Windows Server 2003, IAS is the Microsoft implementation of a Remote Authentication Dial-In User Service (RADIUS) server. In Windows Server operating systems later than Windows Server 2003, IAS is renamed to NPS.
