Getting client remote IP address

[jacknbey]

I have a requirements to log all client activities connected to an IIS server. Problem is that the clients are either connecting via VPN, or via internal Proxy. So the IP addresses the system getting are not really unique if I use the REMOTE_ADDR asp/php/javascript calls.

I read from the Javascript section that no client side scripting can help. I tried few WMI calls from the IIS server to the clients but apparently those will not work since the clients are off company network.

I was wondering why is it so difficult to extract unique client IP address and pass along to the IIS server as a matter of variable.

Can someone share some experiences if you have done that before? I did see the comments of using SSI but I have no idea how to integrate that into the IIS side.

Any help is greatly appreciated

[gil davis]

I couldn't tell from your question whether you understand that one of the goals of VPN or proxy is isolation from techniques to mine the client's identity.

[jacknbey]

That could be true but I am still curious if there are ways to bypass those. How does the logging software did the capturing?