поищи его командой locate

root@Router:/opt/freeradius/sbin# ./check-radiusd-config
Ignoring deprecated command-line option -pStarting - reading configuration files ...
reread_config:  reading radiusd.conf
Config:   including file: /opt/freeradius/etc/raddb/clients.conf
Config:   including file: /opt/freeradius/etc/raddb/cakesql.conf
/opt/freeradius/etc/raddb/radiusd.conf[248]: Unexpected end of file
Errors reading radiusd.conf