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

# 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
2. Execute — Run implementing container network policies with calico workflow with configured parameters
3. 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