Why Default Kubernetes Networking Is Wrong Fresh Kubernetes cluster: Every pod can talk to every other pod Across namespaces, across services, across environments No egress restrictions No ingress restrictions This is a lateral movement attack waiting to happen. One compromised pod = entire cluster. Network Policies fix this. Most teams ignore them until the first security audit. A Simple Rule That Breaks Things Start with: "deny all traffic by default, explicitly allow what you need." apiVersion : networking.k8s.io/v1 kind : NetworkPolicy metadata : name : default-deny-all namespace : production spec : podSelector : {} policyTypes : - Ingress - Egress Enter fullscreen mode Exit fullscreen mode Apply this to a running namespace, and everything breaks : Pods can't reach DNS (kube-dns is in kube-system ) Pods can't reach the API server Metrics scraping fails Service mesh control plane loses connectivity This is not a bug. This is the point. You have to explicitly allow everything.…