In Internet Connection Services for Microsoft Remote Access Service (RAS), a database for providing authentication, access, and accounting information for the users in a given realm. An authentication provider is a server that is used by Internet Authentication Service (IAS) to map a Remote Authentication Dial-In User Service (RADIUS) authentication request to a database containing user credentials. The authentication provider can verify or deny whether the individual exists in the database and return this information to the IAS server. Choices for authentication providers are