Ask any question about Cloud Computing here... and get an instant response.
How do Kubernetes Network Policies restrict pod-to-pod communication?
Asked on Oct 24, 2025
Answer
Kubernetes Network Policies are used to control the communication between pods at the network level, allowing you to define rules that specify which connections are allowed or denied. These policies are crucial for implementing a zero-trust network model within a Kubernetes cluster by managing traffic flow based on namespace, pod labels, and ports.
Example Concept: A Kubernetes Network Policy is a specification of how groups of pods are allowed to communicate with each other and other network endpoints. By default, pods are non-isolated and can communicate with any other pod. When a Network Policy is applied, it selects pods using labels and defines ingress and/or egress rules to allow or deny traffic. These rules can specify sources and destinations by pod labels, namespaces, and IP blocks, effectively creating a firewall at the pod level.
Additional Comment:
- Network Policies are namespace-scoped resources, meaning they only apply to pods within the same namespace.
- To enforce Network Policies, your cluster must have a network plugin that supports them, such as Calico, Cilium, or Weave Net.
- Start with a default deny-all policy to ensure only explicitly allowed traffic is permitted.
- Use labels effectively to define the groups of pods that the policies will apply to.
- Regularly review and update Network Policies to adapt to changes in application architecture and security requirements.
Recommended Links:
