Kubernetes Network Policies let you define which Pods can talk to each other, and which external endpoints they can reach. Without them, every Pod is a node in an open mesh. Attackers love open meshes. Network Policies operate at Layer 3/4, using selectors and rules to block or allow traffic. Create a deny-by-default baseline, then explicitly allow only the flows your application requires. Test with kubectl exec and packet tracing to prove isolation.
While Network Policies control who can connect, TLS (Transport Layer Security) decides whether connections are private and authenticated. In Kubernetes, TLS configuration should start with generating strong certificates—preferably using cert-manager—to handle automatic issuance and rotation. Enforce mutual TLS where services exchange sensitive data, ensuring both client and server verify each other’s identity. Set minimum TLS versions (1.2 or higher) in Ingress controllers and service meshes to block outdated cipher suites.
Combine Network Policies and TLS for layered security. A Pod behind a locked-down policy still risks exposure if traffic is unencrypted or if certificates are weak. Likewise, TLS without network isolation leaves room for lateral movement. Implement both, audit regularly, and integrate them into CI/CD pipelines to detect drift.