How to retrieve the real IP?

Just a simple script, which tries to find the real ip even when a proxy is used...

Code

GeSHi (php):
<?php
// Simple script to retrieve the ip even when a proxy is used
echo getip() . "<br />";
echo gethostbyaddr(getip());
 
function GetIP(){
	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');
	} else {
		$IP = $_SERVER['REMOTE_ADDR'];
	} 
	return $IP;
}
?>
Created by GeSHI 1.0.7.20

I also wrote a script to get the proxy-ip and the user-ip...

Code

GeSHi (php):
<?php
 
$proxy = "No Proxy-Server used or found!";
if (isset($_SERVER['REMOTE_ADDR']))	$ip = $_SERVER['REMOTE_ADDR']; else $ip = 'Unknown';
 
//Proxy detection
  foreach (array('HTTP_X_FORWARDED_FOR', 
  				 'HTTP_X_FORWARDED', 
  				 'HTTP_FORWARDED_FOR',
  				 'HTTP_FORWARDED',
  				 'HTTP_CLIENT_IP') as $x) {
    if (!isset($_SERVER[$x])) continue;
    	$proxy = $ip;
    	$ip = $_SERVER[$x];
  }
 
 
echo 'IP-Adress : ' . $ip . "<br />";
echo 'Hostname  : ' . @gethostbyaddr($ip) ."<br />";
echo 'Proxy     : ' . $proxy . "<br />";
echo 'Hostname  : ' . @gethostbyaddr($proxy);
?> 
 
Created by GeSHI 1.0.7.20