public static function getRealIP()
  {
    if( isset ($_SERVER['HTTP_X_FORWARDED_FOR']) and $_SERVER['HTTP_X_FORWARDED_FOR'] != '' )
    {
      $client_ip = (!empty($_SERVER['REMOTE_ADDR']) ) ? $_SERVER['REMOTE_ADDR'] :
      ( ( !empty($_ENV['REMOTE_ADDR']) )?$_ENV['REMOTE_ADDR']:false );
      $entries = split('[, ]', $_SERVER['HTTP_X_FORWARDED_FOR']);
      reset($entries);
      while (list(, $entry) = each($entries))
      {
        $entry = trim($entry);
        if ( preg_match("/^([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)/", $entry, $ip_list) )
        {
          $private_ip = array(
          '/^0\./',
          '/^127\.0\.0\.1/',
          '/^192\.168\..*/',
          '/^172\.((1[6-9])|(2[0-9])|(3[0-1]))\..*/',
          '/^10\..*/');
          $found_ip = preg_replace($private_ip, $client_ip, $ip_list[1]);
          if ($client_ip != $found_ip)
          {
            $client_ip = $found_ip;
            break;
          }
        }
      }
    }
    else
    {
      $client_ip =( !empty($_SERVER['REMOTE_ADDR']))?$_SERVER['REMOTE_ADDR']:((!empty($_ENV['REMOTE_ADDR']))?
      $_ENV['REMOTE_ADDR']:false );
    }
    return $client_ip;
  }

  public static function getIp()
  {
    if ($_SERVER["HTTP_X_FORWARDED_FOR"] != "")
    {
      $ip = $_SERVER["HTTP_X_FORWARDED_FOR"];
      $ip_array = explode(",", $ip);
      $ip = $ip_array[0];
      $nums 	= sscanf($ip, "%d.%d.%d.%d");
      if ($nums[0] === null || $nums[1] === null || $nums[2] === null || $nums[3] === null || $nums[0] == 10   ||
      ($nums[0] == 172  && $nums[1] >= 16 && $nums[1] = 16 && $nums[1] <= 31) || ($nums[0] == 192  && $nums[1] == 168) ||
      $nums[0] == 239  || $nums[0] == 0 || $nums[0] == 127)
      $ip = $_SERVER["REMOTE_ADDR"];
    }
    else
    $ip = $_SERVER["REMOTE_ADDR"];
    return $ip;
  }

La primera es muy fiable. Si aun asi no salen y si quieres puedes ponerte en contacto con migo y te paso la clase entera