*
   * @param ip {@link Inet6Address} to be examined for Teredo address format
   * @return {@code true} if the argument is a Teredo address
   */
  public static boolean isTeredoAddress(Inet6Address ip) {
    byte[] bytes = ip.getAddress();
    return (bytes[0] == (byte) 0x20)
        && (bytes[1] == (byte) 0x01)
        && (bytes[2] == 0)
        && (bytes[3] == 0);
  }

  /**

    for (String nonTeredoAddress : nonTeredoAddresses) {
      InetAddress ip = InetAddresses.forString(nonTeredoAddress);
      assertFalse(InetAddresses.isTeredoAddress((Inet6Address) ip));
      assertThrows(
          "IllegalArgumentException expected for '" + nonTeredoAddress + "'",
          IllegalArgumentException.class,