Merge pull request #32471 from serewicz/patch-2

install-kubeadm: use nc instead of telnet

Author: k8s-ci-robot

content/en/docs/setup/production-environment/tools/kubeadm/install-kubeadm.md

@@ -69,10 +69,10 @@ For more details please see the [Network Plugin Requirements](/docs/concepts/ext
 ## Check required ports
 These
 [required ports](/docs/reference/ports-and-protocols/)
-need to be open in order for Kubernetes components to communicate with each other. You can use telnet to check if a port is open. For example:
+need to be open in order for Kubernetes components to communicate with each other. You can use tools like netcat to check if a port is open. For example:
 
 ```shell
-telnet 127.0.0.1 6443
+nc 127.0.0.1 6443
 ```
 
 The pod network plugin you use (see below) may also require certain ports to be