hello Everyone, Can anyone please tell that is there any way to run 2 (or more) FREE RADIUS Servers on a single linux machine.

Make a new directory for each server instance. Say you had two. /etc/raddb1 /etc/raddb2 Copy all the files from your original raddb dir to both directories. Modify the files in each directory to do what you want them to do. Make sure to modify the raddbdir variable on the top of each radiusd.conf file. eg: from raddbdir = ${sysconfdir}/raddb to raddbdir = ${sysconfdir}/raddb1 (and raddb2 for the other). Make sure to modify either the bind_address/port variables or the listen directives so you are either a) listening on a different IP for each instance or b) listening on a different port for each instance. eg: (in raddb1) port = 1812 (in raddb2) port = 1645 Then fire them up with the -d option of radiusd. (man radiusd for explanation) eg: $ radiusd -d /etc/raddb1 $ radiusd -d /etc/raddb2 You could open two shells and start up each one in debug mode too. in first shell $ radiusd -X -d /etc/raddb1 from other shell $ radiusd -X -d /etc/raddb2