I've just installed freeradius and start it with a /etc/init.d/ startup script. After I run netstat -nat I dont see that any process is listening on ports 1812 and 1813. I'm using Ubuntu 10.04 LTS and default freeradius configuration. I've tried to manualy edit conf file and to set listening ip addresses and ports, but nothing is changed. I have openbsd-inetd installed but it's turned off. Where could be problem?
RADIUS uses UDP and not TCP. The -t in the netstat command tells it to list TCP ports. Try using lsof instead of netstat to examine UDP ports.
You may also need to restart the RADIUS daemon after changing the config file. You can also use tcpdump to actually see what's going across the wire.