Who Speaks RADIUS? — TechKnowSurge

About this interactive

RADIUS, Remote Authentication Dial-In User Service, is an AAA protocol that has been around since dial-up modems, and it is still widely used. In the lesson's dial-up story, remote sites called a bank of modems at the main office. The server attached to those modems did not keep its own usernames and passwords; it asked the Active Directory side, over RADIUS. The same pattern repeats today. A firewall asks a RADIUS server about a VPN user. A router asks it about an admin logging in with SSH. In 802.1X, the switch or access point asks it about the device on the port. In every case there are three parts. The device the user connects to sends the RADIUS request. A central server answers it, usually checking a directory behind it. The user's own laptop, phone or supplicant never speaks RADIUS at all: it talks to the device in front of it, which carries the login onward.

What you'll learn

Place each device in a RADIUS exchange: the device that sends the request (the firewall, switch, access point, router or modem bank server), the server that answers it, and the user's device, which never speaks RADIUS
Recognize RADIUS centralizing authentication for dial-up, VPN, logins to network devices and 802.1X

Aligned to

CompTIA Security+

1.2 Summarize fundamental security concepts.

4.1 Given a scenario, apply common security techniques to computing resources.

Key terms

Remote Authentication Dial-In User Service: RADIUS is a client-server networking protocol that provides centralized authentication, authorization, and accounting management for users connecting to network access points or VPN services.
Authentication Server: The server in a network access control framework (such as 802.1X) that validates supplicant credentials and grants or denies network access based on authentication policy. RADIUS is the most common authentication server protocol.
802.1X: An IEEE standard for port-based network access control that requires devices to authenticate before gaining access to a wired or wireless network, using a supplicant, authenticator, and authentication server (typically RADIUS). It is the foundation of enterprise Wi-Fi security and wired port security using EAP methods.
Active Directory: Microsoft's directory service used to manage users, computers, and resources in a network.

Topics

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