private function readDomainName($pointer) {
    if (false === $pointer) {
      // Deal with invalid IPs
      $domainName = self::INVALID_IP_ADDRESS;
    } elseif (0 === self::$columns[self::DOMAIN_NAME][$this->type]) {
      // If the field is not suported, return accordingly
      $domainName = self::FIELD_NOT_SUPPORTED;
    } else {
      // Read the domain name
      $domainName = $this->readString($pointer + self::$columns[self::DOMAIN_NAME][$this->type]);
    }
    return $domainName;
  }