Certified Kubernetes Application Developer (CKAD) Practice Test

In the context of Kubernetes networking, what does the default network policy allow?

1. Nothing

2. All Deny

3. All Allow

4. Specific Allow rules defined by the user

The correct answer is: All Allow

In Kubernetes networking, when no network policies are applied to a namespace, the default behavior allows all traffic to and from all pods within that namespace and to/from pods in other namespaces. This means that, by default, any pod can communicate with any other pod without restrictions, implying that all ingress (incoming) and egress (outgoing) traffic is permitted. The option stating "All Allow" correctly reflects this default setting, as it means that there are no constraints on pod communication unless explicitly defined by a custom network policy that enforces specific rules. Custom network policies can limit traffic by specifying which pods are allowed to communicate with one another or with external services, but unless such policies are created, the default state is one of openness, allowing all traffic.