How to get local IP address of the client??

[exceter]

Hi,
I need to know the local ip address of the client connecting to my web site.
for ex,

client (localIP-192.168.1.10) -> Proxy server (IP-212.212.212.212) -> WebServer

how to get the LocalIP address ?
All the following give the IP address of the ProxyServer:
Request.UserHostAddress()
Request.ServerVariables("LOCAL_ADDR")
HttpContext.Current.Request.ServerVariables["LOCAL_ADDR"]
Request.UserHostName()

tnx

Suppose it may be done only with JScript, may somebody help with the code/?...