We recommend installing from packages if possible. Full instructions on building and installing from source code follow.

The mandatory dependencies must be installed before FreeRADIUS can be built. These dependencies are libtalloc and libkqueue, which FreeRADIUS uses for memory management, and platform-independent event handling.

Per-module dependencies that enable support for external services such as LDAP, SQL, etc, are optional. They must be installed for any modules that are to be used. The FreeRADIUS ./configure step will automatically detect if each module has its dependencies met and automatically enable support for them. If the features you require are not enabled you should inspect the configure script output to figure out which additional development libraries need to be installed.

The FreeRADIUS source may be obtained from a number of locations:

The file will be named something like: freeradius-server-4.0.0.tar.gz. Later version will be 4.0.1, or 4.1.0, etc. PGP signatures are also provided for official releases from the FTP site; these are named e.g. freeradius-server-4.0.0.tar.gz.sig.

Un-tar the file, and change to the FreeRADIUS directory (where VERSION below is the version of the server that you have downloaded).

Take the following steps to build and install the server from source:

The installation process will not over-write your existing configuration files. It will, however, warn you about the files it did not install. These will require manual integration with the existing files.

It is generally not possible to reuse configurations between different major versions of the server. (For example - version 2 to version 3, or version 3 to version 4.

For details on what has changed between the version, see the upgrade guide.

We strongly recommend that new major versions be installed in a different location than any existing installations. Any local policies can then be migrated gradually to the configuration format of the new major version. The number of differences in the new configuration mean that is is both simpler and safer to migrate your configurations rather than to try and just get the old configuration to work.

If the server builds and installs, but doesn’t run correctly, then you should first use debugging mode (radiusd -X) to figure out the problem.

This is your best hope for understanding the problem. Read all of the messages which are printed to the screen, the answer to your problem will often be in a warning or error message.

We really cannot emphasize that last sentence enough. Configuring a RADIUS server for complex local authentication isn’t a trivial task. Your best and only method for debugging it is to read the debug messages, where the server will tell you exactly what it’s doing, and why. You should then compare its behaviour to what you intended, and edit the configuration files as appropriate.

If you don’t use debugging mode, and ask questions on the mailing list, then the responses will all tell you to use debugging mode. The server prints out a lot of information in this mode, including suggestions for fixes to common problems. Look especially for WARNING and ERROR messages in the output, and read the related messages.

Since the main developers of FreeRADIUS use debugging mode to track down their configuration problems with the server, it’s a good idea for you to use it, too. If you don’t, there is little hope for you to solve any configuration problem related to the server.

To start the server in debugging mode, do:

You should see a lot of text printed on the screen as it starts up. If you don’t, or if you see error messages, please read the FAQ:

https://wiki.freeradius.org/guide/FAQ

If the server says Ready to process requests., then it is running properly. From another shell (or another window), type

You should see the server print out more messages as it receives the request, and responds to it. The radtest program should receive the response within a few seconds. It doesn’t matter if the authentication request is accepted or rejected, what matters is that the server received the request, and responded to it.

You can now edit the configuration files for your local system. You will usually want to start with sites-enabled/default for main configurations. To set which NASes (clients) can communicate with this server, edit raddb/clients.conf. Please read the configuration files carefully, as many configuration options are only documented in comments in the file.

Note that is is highly recommended that you use some sort of version control system to manage your configuration, such as git or Subversion. You should then make small changes to the configuration, checking in and testing as you go. When a config change causes the server to stop working, you will be able to easily step back and find out what update broke the configuration.

It is also considered a best practice to maintain a staging or development environment. This allows you to test and integrate your changes without impacting your active production environment. You should make the appropriate investment in order to properly support a critical resource such as your authentication servers.

Configuring and running the server MAY be complicated. Many modules have man pages. See man rlm_pap, or man rlm_* for information. Please read the documentation in the doc/ directory. The comments in the configuration files also contain a lot of documentation.

If you have any additional issues, the FAQ is also a good place to start.

https://wiki.freeradius.org/guide/FAQ