RADIUS Overview

RADIUS is an access server AAA protocol developed by Livingston Enterprises, Inc. (now part of Lucent Technologies). It is a system of distributed security that secures remote access to networks and network services against unauthorized access. RADIUS is composed of three components:

  • Protocol with a frame format that uses UDP/IP

  • Server

  • Client

The server runs on a central computer, typically at the customer's site, while the clients reside in the dial-up access servers and can be distributed throughout the network. Cisco incorporated the RADIUS client into Cisco IOS, starting with Cisco IOS Release 11.1.

Client/Server Model

A router operates as a client of RADIUS. The client is responsible for passing user information to designated ...

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