Firewalls are not enough

Kubernetes Network Policies define which pods can talk to each other and to the outside world. Without them, every pod is open to every other pod, a risk that scales with your workloads. A well-crafted Network Policy uses selectors and rules to limit ingress and egress. You can whitelist namespaces, restrict services to internal traffic, and block anything unfamiliar. Apply default-deny first, then allow only what you need. Audit policies often—cloud environments change fast.

Security does not stop at traffic filtering. Kubernetes security certificates secure communication across your cluster. Every API request, webhook, and service connection should use TLS with properly signed certs. Kubernetes uses certificates for API server communication, kubelet authentication, and etcd encryption. Expired, self-signed, or mismanaged certificates open silent tunnels for attackers. Rotate certificates before they expire, use a trusted Certificate Authority, and store them in secure, access-controlled secrets.

Combine Network Policies with strict certificate hygiene. Pods should only talk to trusted endpoints, and every byte of that traffic should be encrypted and validated. Run penetration tests to verify policy rules. Scan the cluster for unused or weak certificates. Document every network and security change so you can roll back if needed.

The strongest clusters don't hope for safety—they enforce it at every packet and handshake.

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