private static Boolean checkIpv6Availability() {
    try {
      return NetworkInterface.networkInterfaces()
          .flatMap(NetworkInterface::inetAddresses)
          .anyMatch(addr -> addr instanceof Inet6Address);
    } catch (final Exception ignore) {
      // Any exception means we treat it as not available.
    }
    return false;
  }
The standard for IPv6 availability is if the machine has any IPv6 addresses.

@return Returns true if any IPv6 addresses are iterable via {@link NetworkInterface}.
util/src/main/java/org/hyperledger/besu/util/NetworkUtility.java