Created: 2008-07-20 18:04
Updated: 2019-03-01 16:35
License: other

The FreeRADIUS server

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The FreeRADIUS Server Project is a high performance and highly configurable multi-protocol policy server, supporting RADIUS, DHCPv4 and VMPS. It is available under the terms of the GNU GPLv2. Using RADIUS allows authentication and authorization for a network to be centralized, and minimizes the number of changes that have to be done when adding or deleting new users to a network.

FreeRADIUS can authenticate users on systems such as 802.1x (WiFi), dialup, PPPoE, VPN's, VoIP, and many others. It supports back-end databases such as MySQL, PostgreSQL, Oracle, Microsoft Active Directory, Apache Cassandra, Redis, OpenLDAP, and many more. It is used daily to authenticate the Internet access for hundreds of millions of people, in sites ranging from 10 to 10 million+ users.


Version 4.0.x of the server is largely compatible with version 3.0.x, but be sure to address any warnings when starting v3.0.x before attempting to use en existing configuration with v4.0.x.

For a list of changes in version 4.0, please see doc/ChangeLog

See raddb/ for information on what to do to update your configuration.

Administrators upgrading from a previous version should install this version in a different location from their existing systems. Any existing configuration should be carefully migrated to the new version, in order to take advantage of the new features which can greatly simply configuration.

Please see and for more information.


To install the server, please see the file in this directory.

Configuring the server

We understand that the server may be difficult to configure, install, or administer. It is, after all, a complex system with many different configuration possibilities.

The most common problem is that people change large amounts of the configuration without understanding what they're doing, and without testing their changes. The preferred method of operation is the following:

  1. Start off with the default configuration files.
  2. Save a copy of the default configuration: It WORKS. Don't change it!
  3. Verify that the server starts - in debugging mode (radiusd -X).
  4. Send it test packets using "radclient", or a NAS or AP.
  5. Verify that the server does what you expect
    • If it does not work, change the configuration, and go to step (3)
    • If you're stuck, revert to using the "last working" configuration.
    • If it works, proceed to step (6).
  6. Save a copy of the working configuration, along with a note of what you changed, and why.
  7. Make a SMALL change to the configuration.
  8. Repeat from step (3).

This method will ensure that you have a working configuration that is customized to your site as quickly as possible. While it may seem frustrating to proceed via a series of small steps, the alternative will always take more time. The "fast and loose" way will be MORE frustrating than quickly making forward progress!

Debugging the Server

Run the server in debugging mode, (radiusd -X) and READ the output. We cannot emphasize this point strongly enough. The vast majority of problems can be solved by carefully reading the debugging output, which includes WARNINGs about common issues, and suggestions for how they may be fixed.

Many questions are answered on the Wiki:

Read the configuration files. Many parts of the server are documented only with extensive comments in the configuration files.

Search the mailing lists. For example, using Google, searching " " will return results from the FreeRADIUS mailing lists.

Feedback, Defects, and Community Support

If you have any comments, or are having difficulty getting FreeRADIUS to do what you want, please post to the 'freeradius-users' list (see the URL above). The FreeRADIUS mailing list is operated, and contributed to, by the FreeRADIUS community. Users of the list will be more than happy to answer your questions, with the caveat that you've read documentation relevant to your issue first.

If you suspect a defect in the server, would like to request a feature, or submit a code patch, please use the GitHub issue tracker for the freeradius-server repository. However, it is nearly always best to raise the issue on the mailing lists first to determine whether it really is a defect or missing feature.

Instructions for gathering data for defect reports can be found in doc/ or on the wiki.

Under no circumstances should the issue tracker be used for support requests, those questions belong on the user's mailing list. If you post questions related to the server in the issue tracker, the issue will be closed and locked. If you persist in positing questions to the issue tracker you will be banned from all FreeRADIUS project repositories on GitHub.

Please do NOT complain that the developers aren't answering your questions quickly enough, or aren't fixing the problems quickly enough. Please do NOT complain if you're told to go read documentation. We recognize that the documentation isn't perfect, but it does exist, and reading it can solve most common questions.

FreeRADIUS is the cumulative effort of many years of work by many people, and you've gotten it for free. No one is getting paid to answer your questions. This is free software, and the only way it gets better is if you make a contribution back to the project ($$, code, or documentation).

We will note that the people who get most upset about any answers to their questions usually do not have any intention of contributing to the project. We will repeat the comments above: no one is getting paid to answer your questions or to fix your bugs. If you don't like the responses you are getting, then fix the bug yourself, or pay someone to address your concerns. Either way, make sure that any fix is contributed back to the project so that no one else runs into the same issue.

Books on RADIUS

See doc/ for more information about FreeRADIUS.

There is an O'Reilly book available. It serves as a good introduction for anyone new to RADIUS. However, it is from 2002 and is not much more than a basic introduction to the subject.

Commercial support

Technical support, managed systems support, custom deployments, sponsored feature development and many other commercial services are available from Network RADIUS.

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