private static ImmutableSet<String> getMachineScopesAndInterfaces() throws SocketException {
    ImmutableSet.Builder<String> builder = ImmutableSet.builder();
    Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
    assertTrue(interfaces.hasMoreElements());
    while (interfaces.hasMoreElements()) {
      NetworkInterface i = interfaces.nextElement();
      builder.add(i.getName()).add(String.valueOf(i.getIndex()));