Mtls Configuration

When to use this skill

Use Mtls Configuration when an AI agent needs a reusable SKILL.md workflow for this job: Configure mutual TLS (mTLS) for zero-trust service-to-service communication. Use when implementing zero-trust networking, certificate management, or securing internal service communication.

When not to use it

Skip Mtls Configuration when the task is outside the coding category, or when a more specific skill in this directory already covers the same workflow with clearer triggers.

How to install

1. Personal install: create ~/.claude/skills/mtls-configuration/SKILL.md (and any bundled scripts) so Claude Code, Claude Desktop, and compatible agents can load it in every project.
2. Project install: commit the same folder at .claude/skills/mtls-configuration/ so teammates get the skill with the repo.
3. Restart the agent session after copying files so it re-scans the skills directory, then ask for the task in words that match the skill description.

Full install guide for Claude, Cursor, and Codex

What this skill does

# mTLS Configuration

Comprehensive guide to implementing mutual TLS for zero-trust service mesh communication.

## When to Use This Skill

- Implementing zero-trust networking - Securing service-to-service communication - Certificate rotation and management - Debugging TLS handshake issues - Compliance requirements (PCI-DSS, HIPAA) - Multi-cluster secure communication

## Core Concepts

### 1. mTLS Flow

``` ┌─────────┐ ┌─────────┐ │ Service │ │ Service │ │ A │ │ B │ └────┬────┘ └────┬────┘ │ │ ┌────┴────┐ TLS Handshake ┌────┴────┐ │ Proxy │◄───────────────────────────►│ Proxy │ │(Sidecar)│ 1. ClientHello │(Sidecar)│ │ │ 2. ServerHello + Cert │ │ │ │ 3. Client Cert │ │ │ │ 4. Verify Both Certs │ │ │ │ 5. Encrypted Channel │ │ └─────────┘ └─────────┘ ```

### 2. Certificate Hierarchy

``` Root CA (Self-signed, long-lived) │ ├── Intermediate CA (Cluster-level) │ │ │ ├── Workload Cert (Service A) │ └── Workload Cert (Service B) │ └── Intermediate CA (Multi-cluster) │ └── Cross-cluster certs ```

## Templates and detailed worked examples

Full template library and detailed worked examples live in `references/details.md`. Read that file when you need the concrete templates.

## Best Practices

### Do's

- **Start with PERMISSIVE** - Migrate gradually to STRICT - **Monitor certificate expiry** - Set up alerts - **Use short-lived certs** - 24h or less for workloads - **Rotate CA periodically** - Plan for CA rotation - **Log TLS errors** - For debugging and audit

### Don'ts

- **Don't disable mTLS** - For convenience in production - **Don't ignore cert expiry** - Automate rotation - **Don't use self-signed certs** - Use proper CA hierarchy - **Don't skip verification** - Verify the full chain

Intended uses

• Implementing zero-trust networking
• Securing service-to-service communication
• Certificate rotation and management
• Debugging TLS handshake issues
• Compliance requirements (PCI-DSS, HIPAA)
• Multi-cluster secure communication