Follow these steps to install and configure Free Radius Server in Linux.

To install MySQL, follow the instructions in the article on how to install MySQL.

Use the apt-get or yum command ot install the freeradius packages.

apt-get install freeradius 
yum install freeradius

apt-get install freeradius-utils
yum install freeradius-utils

apt-get install freeradius-mysql
yum install freeradius-mysql

Add a RADIUS user.

nano /etc/freeradius/users

Add a RADIUS client.

nano /etc/freeradius/clients.conf\nclient 192.168.1.30 {\nsecret=pick something unique\nshortname=router>nastype=cisco}

Restart RADIUS.

service freeradius restart

Use this command to test the RADIUS install.

radtest user1 supersecret localhost 1812 testing123