How can I use Javascript to identify a client?

Question

I have a problem where I cannot identify visitors to my intranet page because their browser is configured to use a proxy, even for the local intranet. I always see the proxy IP and no other details about the client. The SOE that my company uses has the proxy set up already for Firefox and Internet Explorer, and I cannot ask them to reconfigure their browser because that is fairly complicated. I have tried using the PHP $_SERVER['REMOTE_ADDR'] and also one called $HTTP_SERVER_VARS['HTTP_X_FORWARD_FOR']. In fact, I wrote a page that lists both the $_SERVER and $HTTP_SERVER_VARS arrays and there was nothing informative of the actual client connecting. This is why I think it needs to be done on the client's side.

I'm not looking for a secure solution because it is only a simple page, so I was hoping that I could use Javascript or something similar to find something revealing about the client and send it to my intranet page as a GET variable. It's basically for collating statistics. It is no use telling me most of the visitors are a proxy! :)

I also want to avoid having users log in if possible.

Answer 1

I am pretty sure there's no universal way to do this otherwise the whole concept of anonymous proxies go down the drain :)

My advise would be to ask your IT department to configure the proxy to populate the HTTP-X-FORWARD-FOR, REMOTE-ADDR or some other identifying header.

Answer 2

You could use a cookie with a random, unique ID that's set upon the first entrance, and then used for identification. Could be done either in JavaScript or in PHP.