val InetSocketAddress.socketHost: String get() {
      // The InetSocketAddress was specified with a string (either a numeric IP or a host name). If
      // it is a name, all IPs for that name should be tried. If it is an IP address, only that IP
      // address should be tried.
      val address = address ?: return hostName

- Add --permit-address-sharing flag to `kube-apiserver` to listen with `SO_REUSEADDR`. While allowing to listen on wildcard IPs like 0.0.0.0 and specific IPs in parallel, it avoids waiting for the kernel to release socket in `TIME_WAIT` state, and hence, considerably reducing `kube-apiserver` restart times under certain conditions. ([#93861](https://github.com/kubernetes/kubernetes/pull/93861),...

- The `CloudDualStackNodeIPs` feature is now `beta`, meaning that when using
  an external cloud provider that has been updated to support the feature,
  you can pass comma-separated dual-stack `--node-ips` to `kubelet` and have
  the cloud provider take both IPs into account. ([#120275](https://github.com/kubernetes/kubernetes/pull/120275), [@danwinship](https://github.com/danwinship))

- Kube-proxy, when using a Service with External or LoadBalancer IPs on UDP services , was consuming a large amount of CPU because it was not filtering by the Service destination port and trying to delete all the UDP entries associated to the service. ([#130505](https://github.com/kubernetes/kubernetes/pull/130505),...

- Kubelet should now more reliably report the same primary node IP even if the set of node IPs reported by the CloudProvider changes. ([#79391](https://github.com/kubernetes/kubernetes/pull/79391), [@danwinship](https://github.com/danwinship))

- Added the latest GCE pinhole firewall feature, which introduces `destination-ranges` in the ingress `firewall-rules`. It restricts access to the backend IPs by allowing traffic through `ILB` or `NetLB` only. This change does **NOT** change the existing `ILB` or `NetLB` behavior. ([#109510](https://github.com/kubernetes/kubernetes/pull/109510), [@sugangli](https://github.com/sugangli))

Distributions or administrators of Kubernetes may want to control that new Service CIDRs added to the cluster do not overlap with other networks on the cluster, that only belong to a specific range of IPs. Administrators may also prefer to retain the existing behavior of only having one ServiceCIDR per cluster. You can use `ValidatingAdmissionPolicy` to achieve this. ([#128971](https://github.com/kubernetes/kubernetes/pull/128971), [@aojea](https://github.com/aojea))...

* Fixed bug in AWS provider to handle multiple IPs when using more than 1 network interface per ec2 instance. ([#50112](https://github.com/kubernetes/kubernetes/pull/50112), [@jlz27](https://github.com/jlz27))

- Added an e2e test to verify that the cluster is not vulnerable to CVE-2021-29923 when using Services with IPs with leading zeros, note that this test is a necessary but not sufficient condition, all the components in the clusters that consume IPs addresses from the APIs MUST interpret them as decimal or discard them. ([#107552](https://github.com/kubernetes/kubernetes/pull/107552), [@aojea](https://github.com/aojea))

- The `apiserver` exposes 4 new metrics that allow to track the status of the Service CIDRs allocations:
      - current number of available IPs per Service CIDR
      - current number of used IPs per Service CIDR
      - total number of allocation per Service CIDR