- Kubeadm: fixes a preflight check that can fail hostname construction in IPV6 setups ([#134589](https://github.com/kubernetes/kubernetes/pull/134589), [@liggitt](https://github.com/liggitt)) [SIG API Machinery, Auth, Cloud Provider, Cluster Lifecycle and Testing]

### Bug or Regression

- Fix a bug that caused to panic the apiserver when trying to allocate a Service with a dynamic ClusterIP and it has been configured with Service CIDRs with a /28 mask for IPv4 and a /124 mask for IPv6 ([#115334](https://github.com/kubernetes/kubernetes/pull/115334), [@aojea](https://github.com/aojea)) [SIG Network and Testing]

* [IPVS] Introduces flag ipvs-strict-arp to configure stricter ARP sysctls, defaulting to false to preserve existing behaviors. This was enabled by default in 1.13.0, which impacted a few CNI plugins. ([#75295](https://github.com/kubernetes/kubernetes/pull/75295), [@lbernail](https://github.com/lbernail))

  * Report same Node IP as both internal and external. ([#45201](https://github.com/kubernetes/kubernetes/pull/45201), [@abrarshivani](https://github.com/abrarshivani))

  * Filter out IPV6 node addresses. ([#45181](https://github.com/kubernetes/kubernetes/pull/45181), [@BaluDontu](https://github.com/BaluDontu))

- Fixed a regression in kube-proxy where it might refuse to start if given
  single-stack IPv6 configuration options on a node that has both IPv4 and
  IPv6 IPs. ([#121008](https://github.com/kubernetes/kubernetes/pull/121008), [@danwinship](https://github.com/danwinship)) [SIG Network]

     * The value is, e.g. http://localhost:9201 <br>
     * comment: <br>
     * The URL of the search engine HTTP endpoint.<br>
     * For IPv6 environments, use brackets around the IPv6 address (e.g., http://[::1]:9201)
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getSearchEngineHttpUrl();

    /**

### OpenStack

* Fixed a bug in the OpenStack cloud provider where dual stack deployments (IPv4 and IPv6) did not work well when using kubenet as the network plugin. ([#59749](https://github.com/kubernetes/kubernetes/pull/59749), [@zioproto](https://github.com/zioproto))

- Added support to the kube-proxy nodePortAddresses / --nodeport-addresses option to
  accept the value "primary", meaning to only listen for NodePort connections
  on the node's primary IPv4 and/or IPv6 address (according to the Node object).
  This is strongly recommended, if you were not previously using
  --nodeport-addresses, to avoid surprising behavior.

- Kube-proxy doesn't set the sysctl `net.ipv4.conf.all.route_localnet=1` if no IPv4 loopback address is selected by the `nodePortAddresses` configuration parameter. ([#107684](https://github.com/kubernetes/kubernetes/pull/107684), [@aojea](https://github.com/aojea))

- Fix a bug that caused to panic the apiserver when trying to allocate a Service with a dynamic ClusterIP and it has been configured with Service CIDRs with a /28 mask for IPv4 and a /124 mask for IPv6 ([#115333](https://github.com/kubernetes/kubernetes/pull/115333), [@aojea](https://github.com/aojea)) [SIG Testing]