I am not an expert in networking, but I assume this is the command you are talking about:
ubuntu:/etc/freeradius$ sudo netstat -anpu
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
udp 0 0 127.0.0.1:18120 0.0.0.0:* 3777/freeradius
udp 0 0 0.0.0.0:1812 0.0.0.0:* 3777/freeradius
udp 0 0 0.0.0.0:1813 0.0.0.0:* 3777/freeradius
udp 0 0 0.0.0.0:1814 0.0.0.0:* 3777/freeradius
udp 0 0 0.0.0.0:68 0.0.0.0:* 459/dhclient3
> Date: Tue, 25 Mar 2014 13:34:26 +0000
> From: A.L.M.Buxey@lboro.ac.uk
> To: freeradius-users@lists.freeradius.org
> Subject: Re: No remote authentication
>
> Hi,
>
> > but the server debug mode (server side) does not react at all and stay in
> > the waiting for requests state, while the client gets its requests to
> > timeout.
>
> ..so the server doesnt receive the packet at all? in that case check your firewalls
> - eg the server firewall...ensure UDP 1812 is allowed
>
> alan
> -
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