Kubernetes Network Policies Proof of Concept: Isolate and Secure Pod Traffic

A container goes dark. No logs. No packets out. It’s isolated, by design. This is the power of Kubernetes Network Policies, and it starts with a proof of concept you can run fast.

Kubernetes Network Policies control how pods communicate with each other and with external services. Without them, any pod can connect anywhere. With them, you define exact ingress and egress rules at the namespace or pod level. This means tighter security, reduced blast radius, and predictable network behavior.

A Network Policies PoC in Kubernetes shows you the value before you commit to production. Start with a minimal cluster. Use a single namespace for isolation. Create two pods: one that acts as a server, another as a client. By default, both can talk freely.

Then, apply a simple NetworkPolicy yaml:

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
 name: deny-all
 namespace: test-namespace
spec:
 podSelector: {}
 policyTypes:
 - Ingress
 - Egress

This blocks all traffic to and from pods in that namespace. From here, layer in specific allow rules: target selectors, IP blocks, and port ranges. Test every change with kubectl exec and curl between pods to validate enforcement.

For a PoC, document each rule and outcome. Note how policies interact with your CNI plugin. Calico, Cilium, and others may have unique features like global policies or DNS filtering that extend core functionality. Keep the scope narrow and focus on proving isolation and controlled access.

A strong Kubernetes Network Policies PoC delivers three things: verified traffic control, clear YAML templates, and confidence that your cluster can enforce security at the network layer.

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