Definition and Purpose

A recent study by Check Point reports that cyber crime has increased by 40% from 2020 to 2021. This is dangerous for all internet users, but can be especially detrimental to businesses and enterprise organizations.

Remote Authentication Dial-In User Service (RADIUS) is a networking protocol commonly used in enterprise applications like Internet Serve Providers (ISPs) and Virtual Private Networks (VPNs) to access network resources. Moreover, it is commonly used with a Network Access Server (NAS) that is capable of storing and serving resources. The user communicates with this NAS, and upon request forwards an authentication request to a RADIUS server.

This server determines whether or not the user should have access to the requested resources based on given credentials. In response, it may reject, accept, or challenge (ask to provide more information) the request.

Overall, this allows organizations to manage user access of online resources in a more consistent, centralized, and secure manner. It also allows companies to enforce their respective access policies onto users across all relevant networks.

RADIUS Protocol Functions

1. Authentication: When given a request, the RADIUS server can run through verification of the user's credentials and return the proper response to the NAS.
2. Authorization: If requested, additional network resources by the NAS, the RADIUS server can request more authorization information and await a response.
3. Accounting: The RADIUS server can track and record access to its protected network resources, such as session duration and number of accesses by a certain user. It can then collect this data and store it or sent it to be used elsewhere.