# Implementing Container Network Policies With Calico

> Use when 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. Use when working with implementing container network policies with calico.

- Skill: `oyi77/implementing-container-network-policies-with-calico` (Agent Skill)
- Install (CLI): `npx skillmds add oyi77/implementing-container-network-policies-with-calico`
- Raw SKILL.md: https://api.skillmd.com/api/skills/oyi77/implementing-container-network-policies-with-calico/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- License: Apache-2.0
- Author: oyi77 (https://skillmd.com/u/oyi77)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/oyi77/implementing-container-network-policies-with-calico

---


# 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
**Trigger phrases:**
- "implementing container network policies with calico"
- "Enforce Kubernetes network segmentation using Calico CNI network policies and gl"


- 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

```python
# Example: IOC detection
import re

IOC_PATTERNS = {
    "ip": r"\b(?:\d{1,3}\.){3}\d{1,3}\b",
    "domain": r"\b[a-z0-9-]+\.[a-z]{2,}\b",
    "hash_md5": r"\b[a-f0-9]{32}\b",
    "hash_sha256": r"\b[a-f0-9]{64}\b",
}

def extract_iocs(text: str) -> dict:
    return {k: re.findall(v, text) for k, v in IOC_PATTERNS.items()}
```

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: 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.
## When NOT to Use

- You need to test the implementation (use performing-* skills)
- Task is about configuring existing tools (use configuring-* skills)
- You need to analyze security events (use analyzing-* skills)
- Task is about building detection rules (use building-* skills)
- You don't have access to the target environment
- Task requires vendor-specific expertise (consult vendor docs)


## Red Flags

- Performing actions without explicit written authorization from the asset owner
- Testing against production systems without a defined scope and rules of engagement
- Capturing traffic on networks without authorization or privacy considerations
- Leaving packet captures containing sensitive data unencrypted on disk
- Deploying inline blocking rules without testing for false positives first

## Process

1. **Prepare** — Gather requirements, verify prerequisites, set up environment
1. **Execute** — Run implementing container network policies with calico workflow with configured parameters
1. **Verify** — Validate output meets requirements, document results

## Verification

- All steps executed successfully against a test environment before production use
- Output documented with screenshots or logs demonstrating expected behavior
- Captures verified as complete with no dropped packets
- Detection rules tested against known-benign traffic for false positive rate
- Alert thresholds validated and tuned to reduce noise

## Anti-Rationalization Table

| Rationalization | Reality |
|---|---|
| "We are too small to be targeted" | Automated attacks target everyone. Size does not matter. |
| "Security slows us down" | A breach slows you down 100x more. Build security in from the start. |
| "We will fix it after launch" | Vulnerabilities in production are exploited within hours. Fix before deploy. |