Question : Hot to Setup RADIUS Server in Windows ?????

Hi All,
  I am famiiar with ISA proxy Server, IIS Server, Apache server.... I would like to know what is the use of RADIUS (Remote Authentication Dial-In User Service )  server, and how can it be setup in WIndows Network.

I know differnt kinds of Proxy AUthorization like BASIC, NTLM.  

Any help or link will br greatly appreciated.

Regards,
Manjesh

Answer : Hot to Setup RADIUS Server in Windows ?????

"What is the use of proxy?"

here is the principle config, where a radius server is neccessary
                              ___
modem ----/\/\/\---|      |   internal LAN
modem ----/\/\/\---|  R  |-------------------------[RADIUS Server]
modem ----/\/\/\---|      |
modem ----/\/\/\---|  A  |
modem ----/\/\/\---|      |
modem ----/\/\/\---|  S  |----------[core router]--->[internet]
modem ----/\/\/\---|      |
                            -------
The RADIUS server hold all the information, that the user need to connect (usernames, paswords, ip) and also more information, so the telco can change nearly everything inside the authentication packets, where it is needed - it's specialized for the Remote Dial-In (the name says it already).