<code lang="PHP">
//----------------------------------------------------------------
//IsProxy								FUNCTION
//----------------------------------------------------------------
//	What it does - 
//			Checks against public lists of blacklisted
//		proxy addresses to make sure that $IP isn't one of
//		them.
//
//	Changes - 
//		[2006/12/07] - RaX :: Created.
//----------------------------------------------------------------
function IsProxy($IP)
{
	$Result = FALSE;//Innocent until proven Guilty

	$BlackList = array(	'http.dnsbl.sorbs.net',
					'misc.dnsbl.sorbs.net',
					'socks.dnsbl.sorbs.net',
					'proxies.blackholes.easynet.nl',
					'list.dsbl.org'
				 );

	if (preg_match("/([0-9]+).([0-9]+).([0-9]+).([0-9]+)/", $IP, $Matches))
	 {
		foreach ($BlackList as $Server) 
		{
			echo $Server;
			$ServerHost = $Matches[4] . "." . $Matches[3] . "." . $Matches[2] . "." . $Matches[1] . "." . $Server;
			$Resolved = gethostbyname($ServerHost);
			if ($Resolved != $ServerHost)
			{
				$Result = TRUE;//GUILTY!
				break;
			}
		}
	 }
 	return $Result;
}
//-----------------------------------------------------------------
</code>