> I am trying to work will a program that will detect if radius on a machine
> is alive. On connecting to a radius port what response should be expected,
> and what would you send to dissconnect.
There is no connect or disconnect. RADIUS uses udp vice tcp. So there is
no SYN/ACK packets to establish a connection. udp is connectionless so
it just accepts whatever packets are out there coming to it. Telneting
to it gets connection refused. You may try to strobe the port and seeing
if it generates no response or gives an "Invalid protocol" response, but
you are taking the chance of confusing your daemon with invalid packets
that typically should be ignored. Or you can imitate a terminal server's
authentication request and wait for the ACK or NAK response. (This is
probably the most effective way of determining RADIUS status) Read the
RADIUS RFC or whitepapers to get the protocol right.