Internet Authentication Service

Internet Authentication Service (IAS) is a component of Windows Server operating systems that provides centralized user authentication, authorization and accounting. Internet Authentication Service (IAS) is a component of Windows Server operating systems that provides centralized user authentication, authorization and accounting. While Routing and Remote Access Service (RRAS) security is sufficient for small networks, larger companies often need a dedicated infrastructure for authentication. RADIUS is a standard for dedicated authentication servers. Windows 2000 Server and Windows Server 2003 include the Internet Authentication Service (IAS), an implementation of RADIUS server. IAS supports authentication for Windows-based clients, as well as for third-party clients that adhere to the RADIUS standard. IAS stores its authentication information in Active Directory, and can be managed with Remote Access Policies. IAS first showed up for Windows NT 4.0 in the Windows NT 4.0 Option Pack and in Microsoft Commercial Internet System (MCIS) 2.0 and 2.5.