}
		if tc.expectStackDowngrade && len(want.Spec.IPFamilies) > len(got.Spec.ClusterIPs) {
			want.Spec.IPFamilies = want.Spec.IPFamilies[0:1]
		} else if len(got.Spec.IPFamilies) > len(want.Spec.IPFamilies) {
			want.Spec.IPFamilies = append(want.Spec.IPFamilies, got.Spec.IPFamilies[len(want.Spec.IPFamilies):]...)
		}
	}

	if tc.expectNodePorts {
		for i := range want.Spec.Ports {

  //
  // This field may hold a maximum of two entries (dual-stack families, in
  // either order).  These families must correspond to the values of the
  // clusterIPs field, if specified. Both clusterIPs and ipFamilies are
  // governed by the ipFamilyPolicy field.
  // +listType=atomic
  // +optional
  repeated string ipFamilies = 19;

  // IPFamilyPolicy represents the dual-stack-ness requested or required by

	"ipFamilyPolicy":                "IPFamilyPolicy represents the dual-stack-ness requested or required by this Service. If there...

		}
	}

	// match clusterIPs to their families, if they were provided
	if !isHeadlessService(service) && len(service.Spec.ClusterIPs) > 0 && len(service.Spec.IPFamilies) > 0 {
		for i, ip := range service.Spec.ClusterIPs {
			if i > (len(service.Spec.IPFamilies) - 1) {
				break // no more families to check
			}

			// 4=>6
			if service.Spec.IPFamilies[i] == core.IPv4Protocol && netutils.IsIPv6String(ip) {

  //
  // This field may hold a maximum of two entries (dual-stack families, in
  // either order).  These families must correspond to the values of the
  // clusterIPs field, if specified. Both clusterIPs and ipFamilies are
  // governed by the ipFamilyPolicy field.
  // +listType=atomic
  // +optional
  repeated string ipFamilies = 19;

  // IPFamilyPolicy represents the dual-stack-ness requested or required by

	// This field may hold a maximum of two entries (dual-stack families, in
	// either order).  These families must correspond to the values of the
	// clusterIPs field, if specified. Both clusterIPs and ipFamilies are
	// governed by the ipFamilyPolicy field.
	// +listType=atomic
	// +optional
	IPFamilies []IPFamily `json:"ipFamilies,omitempty" protobuf:"bytes,19,opt,name=ipFamilies,casttype=IPFamily"`

	// 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
	IpFamilies []string `protobuf:"bytes,29,rep,name=ipFamilies,proto3" json:"ipFamilies,omitempty"`
	// Controls whether Services are configured to use IPv4, IPv6, or both. Valid options

			intrinsics[intrinsicKey{a, pkg, fn}] = b
		}
	}
	// addF does the same as add but operates on architecture families.
	addF := func(pkg, fn string, b intrinsicBuilder, archFamilies ...sys.ArchFamily) {
		m := 0
		for _, f := range archFamilies {
			if f >= 32 {
				panic("too many architecture families")
			}
			m |= 1 << uint(f)
		}
		for _, a := range all {
			if m>>uint(a.Family)&1 != 0 {

- The `--bind-address` parameter in kube-proxy is misleading, no port is opened with this address. Instead it is translated internally to "nodeIP". The nodeIPs for both families are now taken from the Node object if `--bind-address` is unspecified or set to the "any" address (0.0.0.0 or ::). It is recommended to leave `--bind-address` unspecified, and in particular avoid to set it to localhost (127.0.0.1 or ::1) ([#1195...

- Kube-proxy will now warn at startup if the configuration seems inconsistent
  with respect to IP families. (For example, if you have an IPv4 node IP, but
  `--cluster-cidr` is IPv6.) ([#119003](https://github.com/kubernetes/kubernetes/pull/119003), [@danwinship](https://github.com/danwinship)) [SIG Network]