RADIUS, or Remote Authentication Dial-In User Service, is a widely deployed protocol that enables companies to authenticate, authorize and account for remote users who want access to a system or service from a central network server. RADIUS provides a complete, detailed guide to the underpinnings of the RADIUS protocol. Author Jonathan Hassell brings practical suggestions and advice for implementing RADIUS and provides instructions for using an open-source variation called FreeRADIUS. RADIUS: Securing Public Access to Private Resources