### **Network**

#### **IPv6**

*   [alpha] IPv6 support has been added. Notable IPv6 support details include:
    *   Support for IPv6-only Kubernetes cluster deployments. **<span style="text-decoration:underline;">Note:</span>** This feature does not provide dual-stack support.
    *   Support for IPv6 Kubernetes control and data planes.
    *   Support for Kubernetes IPv6 cluster deployments using kubeadm.

* The pod annotation `security.alpha.kubernetes.io/sysctls` now allows customization of namespaced and well isolated kernel parameters (sysctls), starting with `kernel.shm_rmid_forced`, `net.ipv4.ip_local_port_range` and `net.ipv4.tcp_syncookies` for Kubernetes 1.4. ([#27180](https://github.com/kubernetes/kubernetes/pull/27180), [@sttts](https://github.com/sttts))

- 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.

- Fixed the EndpointSliceController to correctly create endpoints for IPv6-only pods.
  
  Fixed the EndpointController to allow IPv6 headless services, if the IPv6DualStack
  feature gate is enabled, by specifying `ipFamily: IPv6` on the service. (This already

* You can now use `--ipvs-exclude-cidrs` to specify a list of CIDR's which the IPVS proxier should not touch when cleaning up IPVS rules. ([#62083](https://github.com/kubernetes/kubernetes/pull/62083), [@rramkumar1](https://github.com/rramkumar1))

- 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....

- PodLifecycleSleepAction is graduated to GA ([#128046](https://github.com/kubernetes/kubernetes/pull/128046), [@AxeZhan](https://github.com/AxeZhan)) [SIG Architecture, Node and Testing]
- Pods were allowed to use the `net.ipv4.tcp_rmem` and `net.ipv4.tcp_wmem` sysctl by default
  when the kernel version was 4.15 or higher. With the kernel 4.15 the sysctl became namespaced.

### 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]

          sudo sysctl net.ipv6.conf.all.disable_ipv6=0
          sudo sysctl net.ipv6.conf.default.disable_ipv6=0
          make test-pbac

      - name: Test Config File
        run: |
          sudo sysctl net.ipv6.conf.all.disable_ipv6=0
          sudo sysctl net.ipv6.conf.default.disable_ipv6=0
          make test-configfile

      - name: Test Replication
        run: |
          sudo sysctl net.ipv6.conf.all.disable_ipv6=0

          _MINIO_ETCD_TEST_SERVER: ${{ matrix.etcd }}
          _MINIO_OPENID_TEST_SERVER: ${{ matrix.openid }}
        run: |
          sudo sysctl net.ipv6.conf.all.disable_ipv6=0
          sudo sysctl net.ipv6.conf.default.disable_ipv6=0
          make test-iam
      - name: Test with multiple OpenID providers
        if: matrix.openid == 'http://127.0.0.1:5556/dex'
        env: