Q:

Failed binding to auth address 127.0.0.1 port 18120 bound to server inner-tunnel: Address already in use

I have configure freeradius following this tutorial.
But when I run a command
"freeradius -X" 

I got the following error radiusd:

Opening IP addresses and Ports #### listen { type = "auth" ipaddr =
127.0.0.1 port = 18120 Failed binding to auth address 127.0.0.1 port 18120  bound to server inner-tunnel: Address already in use
/etc/freeradius/3.0/sites-  enabled/inner-tunnel[33]: Error binding to
port for 127.0.0.1 port 18120

A:

The process is already running.To fix this run
netstat -tulp | grep "18120" 

check the PID of process, 
then run kill -9 (PID that you got)
rerun freeradius -X

