PHP code to get accurate client IP address

/*
  func: get_client_ip()
  获取客户端IP地址
*/
function get_client_ip()
{
        $ip=false;
        if(!empty($_SERVER["HTTP_CLIENT_IP"]))
        {
            $ip = $_SERVER["HTTP_CLIENT_IP"];
        }
        if (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))
        {
            $ips = explode (", ", $_SERVER['HTTP_X_FORWARDED_FOR']);
            if ($ip)
            {
                array_unshift($ips, $ip); $ip = FALSE;
            }
            for ($i = 0; $i < count($ips); $i++)
            {
                if (!eregi ("^(10|172.16|192.168).", $ips[$i]))
                {
                    $ip = $ips[$i];
                    break;
                }
            }
        }
        return ($ip ? $ip : $_SERVER['REMOTE_ADDR']);
}
?>