Remote Authentication Dial-In User Service (RADIUS)

Defined in RFC 2865 and RFC 2866

What Is It?

“… A [network] protocol for carrying authentication, authorization, and configuration information between a Network Access Server which desires to authenticate its links and a shared Authentication Server.”

The RADIUS protocol is facilitated through the use of a client/server architecture. One of the most popular implementations is FreeRADIUS

When an environment contains tons of network services/devices, it becomes crucial to have the ability to reliably manage access these network resources. RADIUS servers facilitate user authentication, user authorization, and user accounting (AAA).

Network Access Server (NAS)

  • Some type of network service that offers remote users/entties with access to a network’s resources.
  • A NAS typically requires a user to provide some sort of credentials before allowing access.

RADIUS Authentication

  • RADIUS provides a multitude of mechanisms for user authentication to a network device/service.
  • A RADIUS client will provide a users login/password combination. The RADIUS client will then verify these credentials using preconfigured method(s).
  • A client’s authentication request to a server is called an “Access-Request”

Access-Request