func sortIPs(ipList []string) []string {
	if len(ipList) == 1 {
		return ipList
	}

	var ipV4s []net.IP
	var nonIPs []string
	for _, ip := range ipList {
		nip := net.ParseIP(ip)
		if nip != nil {
			ipV4s = append(ipV4s, nip)
		} else {
			nonIPs = append(nonIPs, ip)
		}
	}

	sort.Slice(ipV4s, func(i, j int) bool {
		// This case is needed when all ips in the list

          "home.netscape.com",
          "web.MIT.edu",
          "foo.eDu.au",
          "utenti.blah.IT",
          "dominio.com.co");

  private static final ImmutableSet<String> NON_RS =
      ImmutableSet.<String>builder().addAll(NON_PS).addAll(PS_NOT_RS).build();

  private static final ImmutableSet<String> TOP_UNDER_REGISTRY_SUFFIX =
      ImmutableSet.of("google.com", "foo.Co.uk", "foo.ca.us.");