networkpolicy-debug

Diagnosing Kubernetes NetworkPolicy traffic blocks involves identifying the specific policies selecting a target pod and analyzing their ingress and egress rules. This process pinpoints unexpected traffic blocking caused by default-deny effects or misconfigured rule sets.

A default-deny NetworkPolicy blocks pod connectivity by dropping all ingress or egress traffic that is not explicitly allowed by an additional policy rule. Identifying these restrictive policies requires checking which NetworkPolicies actively select the isolated pod.

To check if your CNI plugin enforces Kubernetes NetworkPolicy, you must verify the cluster's CNI configuration and capabilities. If the CNI lacks enforcement support, applied NetworkPolicy rules will not actually block any network traffic.

Troubleshooting egress NetworkPolicy rules blocking DNS or API server traffic involves examining the egress rules applied to the affected pod. You must verify whether specific exceptions for DNS ports or Kubernetes API server IP addresses are explicitly defined.

Yes, you need kubectl to investigate unexpected traffic blocking from Kubernetes NetworkPolicies. Kubectl provides the cluster interaction required to retrieve NetworkPolicy objects, inspect pod labels, and verify CNI plugin configurations.

Your new microservice fails to communicate after applying a NetworkPolicy because the new rules likely lack the necessary ingress or egress allowances for the existing microservice. Analyzing the applied policy's ingress and egress rules will confirm the exact traffic blockage.