Authentication, authorization, and accounting functionality are the foundation of a network operator’s private networking service. IAS provides an end-to-end solution for building private networks through its integration with the Windows NT security system and other Internet Connection Services for Microsoft® Remote Access Service components.
When a user requests authentication against the corporate authentication server, the RADIUS server at that corporation can compare the authentication request to its data in the Windows NT Domain Controller, where it typically keeps LAN authentication data. The network-access server can be configured to authorize the user to access only the corporation’s server on the network. In this way, a roaming employee can access the corporate network over the Internet by means of a secured connection but cannot “surf the Web” at company expense.
Through a technology called Point-to-Point Tunneling Protocol (PPTP), the user then creates a secure connection (a tunnel) within the Internet to the corporate network. The PPTP authenticates the user once again against the NT Domain Controller, and the user becomes a participant on the corporate network. This server may be configured to encrypt data between the client and itself to keep networking sessions private.