* 2. IPv4: api-server will assign an IP from a `service-cluster-ip-range` that is `ipv4` (either the primary or the secondary, according to how they were configured).
    * 2. IPv6: api-server will assign an IP from a `service-cluster-ip-range` that is `ipv6` (either the primary or the secondary, according to how they were configured).
    * Notes (v1.16):
    * 1. IPVS is the only proxy supported (as of v1.16 ) by Dualstack.

- File content check for IPV4 is now enabled by default, and the check of IPV4 or IPV6 is done for `kubeadm init` or `kubeadm join` only in case the user intends to create a cluster to support that kind of IP address family ([#115420](https://github.com/kubernetes/kubernetes/pull/115420), [@chendave](http...

  This is putting cgroup v1 into a deprecated state. ([#134298](https://github.com/kubernetes/kubernetes/pull/134298), [@kannon92](https://github.com/kannon92)) [SIG Node]

- Kube-proxy no longer falls back from ipvs mode to iptables mode if you ask it to do ipvs but the system is not correctly configured. Instead, it will just exit with an error. ([#111806](https://github.com/kubernetes/kubernetes/pull/111806), [@danwinship](https://github.com/danwinship)) [SIG Network]

  Fixes #135757 ([#135759](https://github.com/kubernetes/kubernetes/pull/135759), [@Abhigyan-Shekhar](https://github.com/Abhigyan-Shekhar)) [SIG API Machinery and CLI]

		if ipV4s[i].IsLoopback() {
			return false
		}
		if ipV4s[j].IsLoopback() {
			return true
		}
		return []byte(ipV4s[i].To4())[3] > []byte(ipV4s[j].To4())[3]
	})

	var ips []string
	for _, ip := range ipV4s {
		ips = append(ips, ip.String())
	}

	return append(nonIPs, ips...)
}

func getConsoleEndpoints() (consoleEndpoints []string) {

  slightly stricter about what values will be accepted as IP addresses and network
  address ranges (“CIDR blocks”).
  
  In particular, octets within IPv4 addresses are not allowed to have any leading
  `0`s, and IPv4-mapped IPv6 values (e.g. `::ffff:192.168.0.1`) are forbidden.
  These sorts of values can potentially cause security problems when different

- Fixed an issue in the Windows kube-proxy (winkernel) where IPv4 and IPv6 Service load balancers could be incorrectly shared, causing broken dual-stack Service behavior. The kube-proxy now tracks load balancers per IP family, enabling correct support for PreferDualStack and RequireDualStack Services on Windows nodes....

        assertEquals("http://127.0.0.1:8080", IpAddressUtil.buildUrl("http", ipv4, 8080, null));

        // IPv4 without port
        assertEquals("http://127.0.0.1", IpAddressUtil.buildUrl("http", ipv4, 0, ""));
        assertEquals("http://127.0.0.1", IpAddressUtil.buildUrl("http", ipv4, -1, ""));

        // IPv6 with port and path
        InetAddress ipv6 = InetAddress.getByName("::1");

    }

    @Test
    void testAddIPAddresses() throws Exception {
        InetAddress ipv4 = InetAddress.getByName("192.168.1.100");
        InetAddress ipv6 = InetAddress.getByName("2001:db8::1");

        notification.addNewIPAddress(ipv4);
        notification.addNewIPAddress(ipv6);
        notification.addOldIPAddress(ipv4);

        List<WitnessNotification.WitnessIPAddress> newAddresses = notification.getNewIPAddresses();