- `kubeproxy_conntrack_reconciler_deleted_entries_total` metric can be used to track cumulative sum of conntrack flows cleared by reconciler. ([#130204](https://github.com/kubernetes/kubernetes/pull/130204), [@aroradaman](https://github.com/aroradaman))

## Changes by Kind

### Feature

- Kubelet TCP and HTTP probes are more effective using networking resources: conntrack entries, sockets, ... 

- Kubelet TCP and HTTP probes are now more effective using networking resources:
  conntrack entries, sockets. This is achieved by reducing the `TIME-WAIT` state
  of the connection to 1 second, instead of the defaults 60 seconds. This allows
  kubelet to free the socket, and free conntrack entry and ephemeral port associated. ([#115143](https://github.com/kubernetes/kubernetes/pull/115143), [@aojea](https://github.com/aojea))

- Optimized kube-proxy conntrack cleanup logic, reducing the time complexity of deleting stale UDP entries. This significantly improves performance when there are many stale connections to clean up. ([#135511](https://github.com/kubernetes/kubernetes/pull/135511), [@aojea](http...

- Fixes a regression introduced in 1.29 where conntrack entries for UDP connections
  to deleted pods did not get cleaned up correctly, which could (among other things)

- During initialization phase (preflight), kubeadm now verifies the presence of the conntrack executable ([#85857](https://github.com/kubernetes/kubernetes/pull/85857), [@hnanni](https://github.com/hnanni)) [SIG Cluster Lifecycle]

* Tune down initialDelaySeconds for readinessProbe. ([#33146](https://github.com/kubernetes/kubernetes/pull/33146), [@MrHohn](https://github.com/MrHohn))
* kube-proxy: Add a lower-bound for conntrack (128k default) ([#33051](https://github.com/kubernetes/kubernetes/pull/33051), [@thockin](https://github.com/thockin))

*   Added iptables rules to allow Pod traffic even when default iptables policy is to reject. ([#52569](https://github.com/kubernetes/kubernetes/pull/52569),[ @tmjd](https://github.com/tmjd))
*   You can once again use 0 values for conntrack min, max, max per core, tcp close wait timeout, and tcp established timeout; this functionality was broken in 1.8. ([#55261](https://github.com/kubernetes/kubernetes/pull/55261),[ @ncdc](https://github.com/ncdc))

#### **CoreDNS**

- Updated CNI plugins to v1.7.1 ([#131602](https://github.com/kubernetes/kubernetes/pull/131602), [@adrianmoisey](https://github.com/adrianmoisey)) [SIG Cloud Provider, Node and Testing]
- Updated `conntrack` reconciler to consider a Service’s target port during cleanup of stale flow entries. ([#130542](https://github.com/kubernetes/kubernetes/pull/130542), [@aroradaman](https://github.com/aroradaman))

- Adds additional testing to ensure that udp pods conntrack are cleaned up ([#90180](https://github.com/kubernetes/kubernetes/pull/90180), [@JacobTanenbaum](https://github.com/JacobTanenbaum)) [SIG Architecture, Network and Testing]