Firewalls no longer stop threats inside Kubernetes. Attackers move laterally, quietly probing containers and services. Without strong network controls, they find their way through. Kubernetes Network Policies and Service Mesh Security are the tools that close those gaps.
Kubernetes Network Policies define which pods can talk to each other and which cannot. They work at the IP and port level, enforced by the underlying CNI plugin. A well-crafted policy can block all traffic except the paths you need. This reduces the chance of compromised pods reaching critical workloads. Use namespace isolation, default deny rules, and least privilege access to keep control tight.
Service Mesh Security goes deeper. Service meshes like Istio or Linkerd give you mTLS between services, secure service discovery, and fine-grained traffic control. They enforce encryption in transit, verify service identity, and manage authorization. Combined with Network Policies, a service mesh adds visibility into requests, allowing detection and blocking of suspicious behavior in real time.