code: 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);
    }
docs: Evaluates whether the argument is a Teredo address.
  
  <p>Teredo addresses begin with the {@code "2001::/32"} prefix.
  
  @param ip {@link Inet6Address} to be examined for Teredo address format
  @return {@code true} if the argument is a Teredo address