// Single number. Some parsers accept this as an IPv4 address in
		// big-endian uint32 form, but we don't.
		"1234",
		// IPv4 with a zone specifier
		"1.2.3.4%eth0",
		// IPv4 field must have at least one digit
		".1.2.3",
		"1.2.3.",
		"1..2.3",
		// IPv4 address too long
		"1.2.3.4.5",
		// IPv4 in dotted octal form
		"0300.0250.0214.0377",
		// IPv4 in dotted hex form
		"0xc0.0xa8.0x8c.0xff",

	}{
		{
			name: "internal k8s service with ipv4 & ipv6 endpoint for Kubernetes TCP protocol",
			instances: []*model.ServiceInstance{
				buildServiceInstance(svc, "10.10.10.10"),
				buildServiceInstance(svc, "fd00:10:244:1::11"),
			},
			services:    []*model.Service{svc},
			listenersOn: "0.0.0.0_9999",
		},
		{
			name: "external service with ipv4 & ipv6 endpoints for Kubernetes auto protocol",

  // Defines which IP family to use for single stack or the order of IP families for dual-stack.
  // Valid list items are "IPv4", "IPv6".
  // More info: https://kubernetes.io/docs/concepts/services-networking/dual-stack/#services
  repeated string ipFamilies = 29;

  // Controls whether Services are configured to use IPv4, IPv6, or both. Valid options
  // are PreferDualStack, RequireDualStack, and SingleStack.

	// a few A records, no AAAA records
	{
		"ipv4.google.com.",
		[]string{
			"nameserver 8.8.8.8",
			"nameserver 2001:4860:4860::8888",
		},
		nil,
		true, false,
	},
	{
		"ipv4.google.com",
		[]string{
			"domain golang.org",
			"nameserver 2001:4860:4860::8888",
			"nameserver 8.8.8.8",
		},
		nil,
		true, false,
	},
	{
		"ipv4.google.com",
		[]string{

const (
	sysctlVSConnTrack             = "net/ipv4/vs/conntrack"
	sysctlConnReuse               = "net/ipv4/vs/conn_reuse_mode"
	sysctlExpireNoDestConn        = "net/ipv4/vs/expire_nodest_conn"
	sysctlExpireQuiescentTemplate = "net/ipv4/vs/expire_quiescent_template"
	sysctlForward                 = "net/ipv4/ip_forward"
	sysctlArpIgnore               = "net/ipv4/conf/all/arp_ignore"

				},
			},
		},
		"good-iprange-ipv4-ipv6": {
			expectedErrors: 0,
			ipRange: &networking.ServiceCIDR{
				ObjectMeta: metav1.ObjectMeta{
					Name: "test-name",
				},
				Spec: networking.ServiceCIDRSpec{
					CIDRs: []string{"192.168.0.0/24", "fd00:1234::/64"},
				},
			},
		},
		"not-iprange-ipv4": {
			expectedErrors: 1,
			ipRange: &networking.ServiceCIDR{

					ClusterIP: "10.0.0.1",
				},
			},
			expectedEndpointFamily: ipv4,
		},
		{
			name:       "v4 service, in a dual stack cluster",
			ipFamilies: ipv4ipv6,
			service: v1.Service{
				Spec: v1.ServiceSpec{
					ClusterIP: "10.0.0.1",
				},
			},
			expectedEndpointFamily: ipv4,
		},
		{
			name:       "v4 service, in a dual stack ipv6-primary cluster",

				{Type: v1.NodeInternalIP, Address: "10.1.1.1"},
				{Type: v1.NodeHostName, Address: testKubeletHostname},
			},
			shouldError: false,
		},
		{
			name:   "Dual-stack cloud, IPv4 first, request IPv4",
			nodeIP: netutils.ParseIPSloppy("0.0.0.0"),
			nodeAddresses: []v1.NodeAddress{
				{Type: v1.NodeInternalIP, Address: "10.1.1.1"},
				{Type: v1.NodeInternalIP, Address: "fc01:1234::5678"},

	// performance over iptables debuggability
	largeClusterEndpointsThreshold = 1000
)

const sysctlRouteLocalnet = "net/ipv4/conf/all/route_localnet"
const sysctlNFConntrackTCPBeLiberal = "net/netfilter/nf_conntrack_tcp_be_liberal"

// NewDualStackProxier creates a MetaProxier instance, with IPv4 and IPv6 proxies.
func NewDualStackProxier(
	ctx context.Context,
	ipt [2]utiliptables.Interface,
	sysctl utilsysctl.Interface,

) (proxy.Provider, error) {
	// Create an ipv4 instance of the single-stack proxier
	ipv4Proxier, err := NewProxier(ctx, v1.IPv4Protocol,
		syncPeriod, minSyncPeriod, masqueradeAll, masqueradeBit,
		localDetectors[v1.IPv4Protocol], hostname, nodeIPs[v1.IPv4Protocol],
		recorder, healthzServer, nodePortAddresses, initOnly)
	if err != nil {
		return nil, fmt.Errorf("unable to create ipv4 proxier: %v", err)
	}