By default, every pod in a Kubernetes cluster can communicate with every other pod without restriction. This flat-trust networking model — inherited from the days when clusters ran a single application — is a security nightmare in production. A compromised pod in the default namespace can probe databases, scrape secrets from control-plane components, or exfiltrate data to an external server. Kubernetes Network Policies are the primary mechanism to break this implicit trust and enforce zero-trust segmentation at the network layer.
Network Policies turn your cluster from a flat free-for-all into a segmented, least-privilege environment where each pod explicitly declares which traffic it expects and which traffic it denies. Without them, a single vulnerability in one microservice can cascade into a full cluster compromise. This guide covers everything you need to know — from basic policy syntax to advanced patterns with Cilium, Egress NAT, and multi-tenant isolation.
Why Default Kuberne
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👉 Read the full article on ShieldOps: https://shieldops-ai.dev/blog/kubernetes-network-policies-enforcing-zero-trust-at-the-network-layer
Originally published on ShieldOps Blog.
