Showing a users IP

I am very new to coding and need some help.  I have numerous sites that show scripts on how to show a users IP address using scripts like;

$ip = getenv('REMOTE_ADDR');
echo("<br/>Your IP Address is $ip");

the above works fine for internet users who are not using NAT or proxie.  I would like to be able to get both the Users PC IP address as well as the users gateway/proxie address.  I would like my site to show BOTH the REMOTE_ADDR and the USERS PC ADDRESS.

Any help would be very much appreciated.

Who is Participating?
Drift3rConnect With a Mentor Commented:
Well ... that works with java because java runs in the client side and has local access and Network libraries to manipulate that kind of info... you'll never do it with PHP because it runs on the server side ... not even with javascript you can get it unless you use javascript to call java ... like in this example:

or this one:

It's still a long shot as I think the user has to have Java installed ... not everybody has ... so there's really no sure way to get what you want ...

Either way ... Why do you want a nat address? What's the use? If he's on DHCP next time he'll probably have a different IP. Even if he has the same IP ... about 10 million other people can have the same IP ... (as it is a private IP) ... what's the use?
That isn't possible. If the user is behind a NAT firewall or proxy, then you can not get their IP address. That is one of the biggest advantages to using NAT. Otherwise, if you could still get a user's -private- IP address, then it wouldn't be private, and it wouldn't be safe.

Users will only have one IP address and that will be either their computer or their firewall / proxy. That IP address is available in the REMOTE_ADDR variable like you've been using. Sorry!
Hum ... it depends on the configuration ... the proxy problem can be addressed ...

check this ... I already answered a question addressing this problem ...

It is not possible to get the address of everyone nevertheless ... it depends on configurations of the firewalls proxys etc which are beyond your control.
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broadspokeAuthor Commented:
Thanks for the comments.  But, I think there has to be a way to do this.  I found and example on line that uses a Java Applet and it works.  I know because I am behind a NAT'd network.  I do not understand how to make a Java Applet and prefer PHP for most of my code.  

If y9ou can offfer some help I would really be grateful.

Site that works.


Just to give you an example ... my machine appears in that applet like this:

Your local IP address is
Your global IP address is <?=$REMOTE_ADDR?>
It would appear that your machine does use NAT.
Your machine has an IP address of,
but your browser connected to this page from <?=$REMOTE_ADDR?>!
You are in the private range: - (10/8 prefix)

See the <?=$REMOTE_ADDR?> ... it can't get that ...
Maybe you should try use this get IP function

This function checks if user is coming behind proxy server and also tries to get the real IP
Note that getenv() function doesn't work when PHP is running as ISAPI module


function ip_address()

      if (getenv('HTTP_CLIENT_IP'))
             $ip = getenv('HTTP_CLIENT_IP');
      elseif (getenv('HTTP_X_FORWARDED_FOR'))
            $ip = getenv('HTTP_X_FORWARDED_FOR');
      elseif (getenv('HTTP_X_FORWARDED'))
            $ip = getenv('HTTP_X_FORWARDED');
      elseif (getenv('HTTP_FORWARDED_FOR'))
            $ip = getenv('HTTP_FORWARDED_FOR');
      elseif (getenv('HTTP_FORWARDED'))
            $ip = getenv('HTTP_FORWARDED');
            $ip = $_SERVER['REMOTE_ADDR'];
                return $ip;


j311y :)
Everyone else has pretty much summed it up. Like Drifter said, the Java applet works because its client side portion has access to that information. But as soon as the workstation sends a request through a proxy/firewall with NAT, it loses the internal IP and it's up to the firewall or proxy to provide that information (and most don't). I don't mean to be a downer, but that's just one issue that you have to work with when dealing with server-side programming.

If you have control over the firewall or proxy, then that's a different story, since you could program the device/software to provide that IP, but chances are that that's not your situation.

- J
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