Implementing Container Network Policies With Calico

---
name: implementing-container-network-policies-with-calico
license: Apache-2.0
description: Enforce Kubernetes network segmentation using Calico CNI network policies and global network policies to control pod-to-pod traffic, restrict egress, and implement zero-trust microsegmentation.
metadata:
  domain: cybersecurity
  subdomain: container-security
  tags:
  - container-security
  - kubernetes
  - calico
  - network-policy
  - microsegmentation
  - cni
  version: '1.0'
  author: mahipal
---
# Implementing Container Network Policies with Calico

## Overview

Calico provides Kubernetes-native and extended network policy enforcement through its CNI plugin. This skill covers creating and auditing Calico NetworkPolicy and GlobalNetworkPolicy resources to implement pod-to-pod traffic control, namespace isolation, egress restrictions, and DNS-based policy rules using calicoctl and the Kubernetes API.


## When to Use

- When deploying or configuring implementing container network policies with calico 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 Calico CNI installed
- Python 3.9+ with `kubernetes` client library
- calicoctl CLI tool installed and configured
- kubectl access with RBAC permissions for network policy management

## Steps

### Step 1: Audit Existing Network Policies
Use calicoctl and kubectl to inventory current network policies and identify unprotected namespaces.

### Step 2: Implement Default-Deny Policies
Create default-deny ingress and egress policies per namespace as a zero-trust baseline.

### Step 3: Create Workload-Specific Allow Rules
Define granular allow rules for legitimate pod-to-pod and pod-to-service communication.

### Step 4: Validate Policy Enforcement
Test connectivity between pods to verify policies are correctly enforced.

## Expected Output

JSON audit report listing all network policies, unprotected namespaces, policy rule counts, and connectivity test results.