FreeRADIUS Documentation

Configuring the server can be a complex task. This task is made easier in recent versions, as we gradually improve the documentation and "default" configurations.

The online documentation is automatically built from the doc directory which comes with the server. Every configuration file contains detailed documentation on what the file does, and what can be configured. The raddb/sites-available directory contains many example "virtual servers". Each example has comments describing what it does, when it should be used, and how to configure it.

If you are using version 1 or 2 of the server, we suggest upgrading to version 3. Versions 1 and 2 are both end-of-life and no longer supported.

Many people try to find documentation by searching for things online. This method is not generally productive. It is easy to get lost in a mess of contradictory and confusing documentation, which leads to frustration and a badly configured server.

Most third-party documentation and How-To's are wrong and outdated. We strongly suggest that you do not follow any documentation which is more than 4 years old. If you do follow such ancient documentation, the result will likely be a server that does not work.

The server contains a substantial amount of documentation and examples. We strongly suggest reading the configuration files before editing them. We also suggest a slow and methodical approach to changing the configuration. Making many changes at once will generally not work.

New to RADIUS? Start here.

Quick Start guide

New users of the server should read Getting Started. It describes how to set up a test user and how to add a new client. These are the two basic steps that start all new installations.

FreeRADIUS Technical Guide (PDF)

This comprehensive guide covers RADIUS concepts, how RADIUS works, and how to install FreeRADIUS. It also describes configuration files distributed with the server and what they are used for.

Download the FreeRADIUS Technical Guide (PDF)


The Wiki has a fair amount of documentation and How-To's. It is a good starting resource. The Wiki is searchable: type in a few keywords, and you will get pages of documentation that often answer your questions and can help you solve problems.

Contributing to the documentation

You can help! Just edit the wiki. It takes less than five minutes, and it will help thousands of other people.


Our documentation is a work in process and is as yet incomplete. However, we have extensive documentation on the following topics:

Links of interest:


All of the "man" pages are available on any system running FreeRADIUS. We suggest typing typing man radiusd, and reading the resulting text. These manual pages contain instructions for configuring and debugging the server.

Links of interest:


The doc site holds a rendered copy of the doxygen annotations added to the FreeRADIUS code base. Doxygen content is primarily useful for developers, but it contains notes describing hidden or advanced features that may be useful for users.

The API documentation site is not useful for people who want to configure FreeRADIUS.


This web site has a number of useful how-to documents that are kept up to date with newer versions of the server.

Links of interest:


Many Request for Comments (RFC) documents have been written over the years that build up the de-facto standards used in implementing RADIUS solutions. They are listed here for convenience.