Anthropic-Cybersecurity-Skills/skills/implementing-container-network-policies-with-calico/SKILL.md

---
name: implementing-container-network-policies-with-calico
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.
domain: cybersecurity
subdomain: container-security
tags: [container-security, kubernetes, calico, network-policy, microsegmentation, cni]
version: "1.0"
author: mahipal
license: MIT
---
# 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.

## 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.