Let A.B.C.D be the public IP of my VPN server. Let W.X.Y.Z be the IP of the client before it connects to the VPN.
My VPN server's IP address on the LAN in 10.8.0.1, and the client is 10.8.0.6. I also run a webserver on the same machine hosting the VPN. On it is a simple webpage that performs the exact same thing as whatismyip.org (i.e., simply prints the IP of the requester)
Let me illustrate the scenario for you.
In a Chrome window I have three tabs, what I have in parenthesis is the URL:
Tab 1 (http://whatismyip.org):
This is what I expect to see. It's the public IP of the VPN server.
Tab 2 (http://10.8.0.1):
ok, looks expected. They are behind the same LAN now.
Tab 3 (http://A.B.C.D)
WTF?? Basically, if I access the webserver while tunneled, in shows the IP address of my machine PRIOR to tunelling!
Remember, tab2 and tab3 are the same webpage. Why does Tab3 not show the client IP as it's own IP (i.e., show A.B.C.D)???
I hope this question is clear, thanks in advance!