Help needed with PHP Server Requests behind firewalls/proxy

Does anybody know how to work with local IP address with PHP but behind a firewall or perhaps the problem is a proxy?

More specifically, I am working on a webpage for work where I want a link to only appear on three computers based on some unique identifier. The trouble I seem to run into is the fact that we are operating from behind a firewall so I only ever get the same IP address no matter how I request it.

When I have researched local IP address and all the variations, I am always returning the same "local IP address" no matter which computer I am on. I have tried seeing if it was possible to do MAC address, or some other single computer specific information, but I have not had any luck.

Ignoring specific formatting, here is something like what I am trying to do:

$localip = $_SERVER["HTTP_CLIENT_IP"]
if ($localip == xxx.xxx.xxx.xxx) {print "<a href='link.php'>Link Title</a>";}

I have already reviewed and tried every option on this page: http://us.php.net/manual/fr/reserved.variables.server.php

Any suggestions? All possible leads and information are greatly appreciated! Thanks!

Jamesbot said:

do you have any authentication mechanism?

one thought off the top of my head would be to create a page that will place a cookie on the client machine. that would how you specifically identify the client. that page could be password protected using something simple like a .htaccess file.

from then on once they have the cookie, then code it so the link appears only to the users that have the cookie.

Click to expand...

Thanks for the thoughts. Well, if I understand well enough, yes, I do have an authentication mechanism. There are accounts established, and it is after they log into their account on one specific computer, that I want the link to show up. My concern with a .htaccess cookie would be the control.

Would I be able to have a cookie only be established to show this link on a single computer? They need to access this page from multiple computers, but I only want the link to be shown on the single access computer. Would the cookie method you are proposing accomplish this?