PHP Inform

Get real IP address if user has transportent proxy

<?PHP

function getip () 
{ 
if ( getenv ( "HTTP_CLIENT_IP" ) & & strcasecmp ( getenv ( "HTTP_ CLIENT_IP" ), "unknown" )) 
$ip = getenv ( "HTTP_CLIENT_IP" );

elseif ( getenv ( "HTTP_X_ FORWARDED_FOR" ) && strcasecmp ( getenv ( "HTTP_X_ FORWARDED_FOR" ), "unknown" )) 
$ip = getenv ( "HTTP_X_FORWARDED_FOR" ) ;

elseif ( getenv ( "REMOTE_ADDR" )  && strcasecmp ( getenv ( "REMOTE_ ADDR" ), "unknown" )) 
$ip = getenv ( "REMOTE_ADDR" );

elseif (!empty( $_SERVER [ ' REMOTE_ADDR' ]) && strcasecmp ( $_SERVER [ 'REMOTE_ ADDR' ], "unknown" )) 
$ip = $_SERVER [ 'REMOTE_ADDR' ];

else 
$ip = "unknown" ;

return( $ip ); 
} 
?>