implementing-network-policies-for-kubernetes

name	implementing-network-policies-for-kubernetes
description	Kubernetes NetworkPolicies provide pod-level network segmentation by defining ingress and egress rules that control traffic flow between pods, namespaces, and external endpoints. Combined with CNI plu. Use when working with implementing network policies for kubernetes.
domain	cybersecurity
subdomain	container-security
tags	["containers","kubernetes","security","network-policies","microsegmentation"]
version	1.0
author	oyi77
license	Apache-2.0
nist_csf	["PR.PS-01","PR.IR-01","ID.AM-08","DE.CM-01"]

Implementing Network Policies for Kubernetes

Overview

Kubernetes NetworkPolicies provide pod-level network segmentation by defining ingress and egress rules that control traffic flow between pods, namespaces, and external endpoints. Combined with CNI plugins like Calico or Cilium, network policies enforce zero-trust microsegmentation to prevent lateral movement within the cluster.

When to Use

Trigger phrases:

• "implementing network policies for kubernetes"

• "Kubernetes NetworkPolicies provide pod-level network segmentation by defining in"

• When deploying or configuring implementing network policies for kubernetes capabilities in your environment

• When establishing security controls aligned to compliance requirements

• When building or improving security architecture for this domain

• When conducting security assessments that require this implementation

Prerequisites

• Kubernetes cluster with NetworkPolicy-supporting CNI (Calico, Cilium, Antrea)
• kubectl configured with admin access
• Understanding of pod labels and selectors

Workflow

1. Scope the task — define objectives, boundaries, and success criteria
2. Gather information — collect all necessary data and context before proceeding
3. Execute the core workflow — follow the domain-specific steps methodically
4. Validate results — verify outputs against expected outcomes or baselines
5. Document findings — record results, anomalies, and recommendations

Step 1: Default Deny All Traffic

# default-deny-all.yaml - Apply to every namespace
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: default-deny-all
  namespace: production
spec:
  podSelector: {}  # Applies to all pods
  policyTypes:
    -