Free Containerlab Network Labs 🚀

Modern, lightweight network labs using Containerlab and FRR routing

Learn OSPF, BGP, and Linux networking with hands-on containerized labs. No VMs required!

Why Containerlab?

Traditional network labs (GNS3, EVE-NG) require heavy virtual machines and complex setup. These containerized labs offer:

• ✅ 75% less memory - ~50MB per router vs 1GB+ for VM-based labs
• ✅ 96% faster startup - 30 seconds vs 10+ minutes
• ✅ Zero configuration - One-click deployment with VS Code devcontainers
• ✅ Modern approach - Docker containers, not VMs

🎓 Available Labs

Lab	Difficulty	Time	Topics	Tests
OSPF Basics	⭐⭐ Beginner	45 min	OSPF single-area, neighbor adjacency, DR/BDR election	6
BGP eBGP Basics	⭐⭐ Beginner	60 min	eBGP peering, AS-path, route advertisement	6
Linux Network Namespaces	⭐ Beginner	30 min	Network namespaces, veth pairs, IP forwarding	5

1. OSPF Basics

Learn OSPF fundamentals with a simple 3-router topology. Perfect for understanding OSPF operation, DR/BDR election, and basic troubleshooting.

→ Start OSPF Lab

2. BGP eBGP Basics

Understand external BGP with a 4-router, 3-AS topology. Learn BGP neighbor establishment, route propagation, and AS-path manipulation.

→ Start BGP Lab

3. Linux Network Namespaces

Explore how containerlab uses Linux network namespaces to create isolated network environments. Understand the foundation of container networking.

→ Start Linux Namespaces Lab

✨ SSH Access to Routers

All labs include SSH access with auto-login to router CLI - just like real Cisco/Juniper routers!

Credentials:

• Username: admin
• Password: cisco

Access methods:

1. VS Code Extension (easiest) - Right-click container → SSH
2. Port mapping - ssh -p 2221 admin@localhost
3. Container name - ssh admin@clab-ospf-basics-r1

You land directly at the router CLI:

$ ssh -p 2221 admin@localhost
Password: cisco

r1#  ← Router CLI (not bash shell!)
r1# show ip ospf neighbor
r1# show ip route

See SSH-SETUP-COMPLETE.md for complete documentation.

🚀 Quick Start

Prerequisites

# Install containerlab (Linux/Mac)
bash -c "$(curl -sL https://get.containerlab.dev)"

# Verify installation
containerlab version

Run a Lab

# Clone this repo
git clone https://github.com/ciscoittech/containerlab-free-labs.git
cd containerlab-free-labs

# Build frr-ssh image (first time only)
./build-frr-ssh.sh

# Option 1: Run in VS Code with devcontainer (recommended)
cd ospf-basics
code .  # Click "Reopen in Container"

# Option 2: Run locally
cd ospf-basics
sudo containerlab deploy -t topology.clab.yml

# Access routers via SSH (recommended)
ssh -p 2221 admin@localhost  # OSPF r1
# Password: cisco
# Lands directly at router CLI: r1#

# Alternative: Docker exec
docker exec -it clab-ospf-basics-r1 vtysh

# Cleanup
sudo containerlab destroy -t topology.clab.yml

📚 Learning Path

1. Start here: Linux Network Namespaces (understand the foundation)
2. OSPF Basics: Learn link-state routing protocols
3. BGP eBGP Basics: Understand internet routing fundamentals

🤝 Contributing

Contributions are welcome! See CONTRIBUTING.md for guidelines.

Quick start:

1. Fork this repo
2. Create a feature branch (git checkout -b feature/new-lab)
3. Test in devcontainer (./scripts/validate.sh)
4. Submit a PR

Want to add a lab? Check our lab template

📖 Resources

• Containerlab Documentation
• FRRouting Documentation
• Network Automation Community

📜 License

MIT License - Use these labs for learning, teaching, or building your own projects!

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Note: These labs use FRR (Free Range Routing) which provides Cisco-like syntax for BGP, OSPF, IS-IS, and more. Perfect for CCNA/CCNP lab practice without expensive hardware!