IP Address of Client after IISProxy.dll configured

Hi,

We have a requirement to capture IP address of client. we are able to do it when the users access the portal from inside the firewall using portal url. http://<servername>:port/irj

but when users access the portal outside the firewall we have IISproxy.dll configured which redirects requests from IIS server to our ep server. so everytime when we try to capture ip address we get the ipaddress of the IIS web server instead of user ip address.

one possible way could be get the ip address of the user on IIS server and send it as a parameter in redirected request to ep server.

Any suggestions?