# Minimalistic WireGuard VPN Setup

**Purpose**: Secure admin access to internal services (Traefik Dashboard, Prometheus, Grafana, etc.)

**Architecture**: Host-based WireGuard with IP-based service access (no DNS required)

## Overview

```
Public Internet
    ↓
┌─────────────────────────────────────────┐
│ Server (Public IP)                      │
│                                         │
│ Public Ports:                           │
│   80/443  → Traefik (Public Apps)       │
│   22      → SSH                         │
│   51820   → WireGuard                   │
│                                         │
│ VPN Network (10.8.0.0/24):              │
│   10.8.0.1 → Server (VPN Gateway)       │
│                                         │
│ Admin Services (VPN-only):              │
│   https://10.8.0.1:8080  → Traefik      │
│   http://10.8.0.1:9090   → Prometheus   │
│   https://10.8.0.1:3001  → Grafana      │
│   http://10.8.0.1:9000   → Portainer    │
│   http://10.8.0.1:8001   → Redis Insight│
│                                         │
└─────────────────────────────────────────┘
```

## Components

### 1. WireGuard (Host-based)
- **Interface**: wg0
- **Server IP**: 10.8.0.1/24
- **Port**: 51820/udp
- **Management**: systemd + wg-quick

### 2. nftables Firewall
- **VPN Access**: 10.8.0.0/24 → All admin services
- **Public Access**: Only ports 80, 443, 22
- **Default Policy**: DROP all other traffic

### 3. Service Access (IP-based)

| Service | URL | Purpose |
|---------|-----|---------|
| Traefik Dashboard | https://10.8.0.1:8080 | Reverse Proxy Management |
| Prometheus | http://10.8.0.1:9090 | Metrics Collection |
| Grafana | https://10.8.0.1:3001 | Monitoring Dashboards |
| Portainer | http://10.8.0.1:9000 | Docker Management |
| Redis Insight | http://10.8.0.1:8001 | Redis Debugging |

## Quick Start

### Server Setup (Automated)

```bash
# Deploy WireGuard + Firewall
cd deployment/ansible
ansible-playbook playbooks/setup-wireguard-host.yml
```

### Client Setup

```bash
# Generate new client config
cd deployment/scripts
./generate-client-config.sh michael-laptop

# Import config (Linux/macOS)
sudo wg-quick up ./configs/michael-laptop.conf

# Import config (Windows)
# 1. Open WireGuard GUI
# 2. Import Tunnel from File
# 3. Select ./configs/michael-laptop.conf

# Import config (iOS/Android)
# Scan QR code generated by script
```

### Verify Connection

```bash
# Check VPN connection
ping 10.8.0.1

# Access Traefik Dashboard
curl -k https://10.8.0.1:8080
```

## Manual Server Setup

If you prefer manual installation:

### 1. Install WireGuard

```bash
# Ubuntu/Debian
sudo apt update
sudo apt install wireguard wireguard-tools qrencode

# Check kernel module
sudo modprobe wireguard
lsmod | grep wireguard
```

### 2. Generate Server Keys

```bash
# Create config directory
sudo mkdir -p /etc/wireguard
cd /etc/wireguard

# Generate keys
umask 077
wg genkey | tee server_private.key | wg pubkey > server_public.key

# Save keys
SERVER_PRIVATE_KEY=$(cat server_private.key)
SERVER_PUBLIC_KEY=$(cat server_public.key)
```

### 3. Create Server Config

```bash
sudo tee /etc/wireguard/wg0.conf <<EOF
[Interface]
PrivateKey = $SERVER_PRIVATE_KEY
Address = 10.8.0.1/24
ListenPort = 51820

# Firewall: Allow VPN traffic forwarding
PostUp = nft add table inet wireguard
PostUp = nft add chain inet wireguard postrouting { type nat hook postrouting priority srcnat\; }
PostUp = nft add chain inet wireguard forward { type filter hook forward priority filter\; }
PostUp = nft add rule inet wireguard postrouting oifname "eth0" ip saddr 10.8.0.0/24 masquerade
PostUp = nft add rule inet wireguard forward iifname "wg0" accept
PostUp = nft add rule inet wireguard forward oifname "wg0" ct state established,related accept

PostDown = nft delete table inet wireguard

# Peers will be added here
EOF

# Secure permissions
sudo chmod 600 /etc/wireguard/wg0.conf
```

### 4. Enable WireGuard

```bash
# Enable IP forwarding
echo "net.ipv4.ip_forward = 1" | sudo tee -a /etc/sysctl.conf
sudo sysctl -p

# Start WireGuard
sudo systemctl enable wg-quick@wg0
sudo systemctl start wg-quick@wg0

# Check status
sudo wg show
sudo systemctl status wg-quick@wg0
```

### 5. Apply Firewall Rules

See `deployment/ansible/templates/wireguard-firewall.nft.j2` for complete firewall configuration.

```bash
# Allow WireGuard port
sudo nft add rule inet filter input udp dport 51820 accept

# Allow VPN network to access admin services
sudo nft add rule inet filter input ip saddr 10.8.0.0/24 tcp dport { 8080, 9090, 3001, 9000, 8001 } accept

# Block public access to admin services
sudo nft add rule inet filter input tcp dport { 8080, 9090, 3001, 9000, 8001 } drop
```

## Client Configuration

### Generate Client

```bash
# Generate client keys
umask 077
wg genkey | tee client_private.key | wg pubkey > client_public.key
wg genpsk > client_preshared.key

CLIENT_PRIVATE_KEY=$(cat client_private.key)
CLIENT_PUBLIC_KEY=$(cat client_public.key)
CLIENT_PSK=$(cat client_preshared.key)
```

### Add Client to Server

```bash
# Add peer to server config
sudo tee -a /etc/wireguard/wg0.conf <<EOF

[Peer]
# michael-laptop
PublicKey = $CLIENT_PUBLIC_KEY
PresharedKey = $CLIENT_PSK
AllowedIPs = 10.8.0.2/32
EOF

# Reload WireGuard
sudo systemctl reload wg-quick@wg0
```

### Create Client Config File

```bash
# Create client config
cat > michael-laptop.conf <<EOF
[Interface]
PrivateKey = $CLIENT_PRIVATE_KEY
Address = 10.8.0.2/32
DNS = 1.1.1.1, 9.9.9.9

[Peer]
PublicKey = $SERVER_PUBLIC_KEY
PresharedKey = $CLIENT_PSK
Endpoint = YOUR_SERVER_IP:51820
AllowedIPs = 10.8.0.0/24
PersistentKeepalive = 25
EOF
```

## Troubleshooting

### VPN Not Connecting

```bash
# Check WireGuard status
sudo wg show

# Check firewall
sudo nft list ruleset | grep 51820

# Check logs
sudo journalctl -u wg-quick@wg0 -f

# Test connectivity
ping 10.8.0.1  # From client
```

### Cannot Access Services

```bash
# Verify firewall allows VPN network
sudo nft list ruleset | grep "10.8.0.0"

# Check service is listening
sudo ss -tlnp | grep 8080  # Traefik Dashboard

# Test from VPN
curl -k https://10.8.0.1:8080  # From client
```

### Key Rotation

Recommended: Rotate keys annually

```bash
# Generate new server keys
cd /etc/wireguard
wg genkey | tee server_private_new.key | wg pubkey > server_public_new.key

# Update server config
# ... update PrivateKey in wg0.conf

# Regenerate all client configs with new server PublicKey
# ... update clients

# Restart WireGuard
sudo systemctl restart wg-quick@wg0
```

## Security Best Practices

### 1. Strong Cryptography
- ✅ WireGuard uses modern crypto (ChaCha20, Poly1305, Curve25519)
- ✅ Preshared keys for quantum resistance
- ✅ Perfect forward secrecy

### 2. Firewall Isolation
- ✅ Admin services only accessible via VPN
- ✅ Explicit ALLOW rules, default DROP
- ✅ Rate limiting on VPN port (optional)

### 3. Key Management
- ✅ Private keys never leave server/client
- ✅ Preshared keys for each peer
- ✅ Annual key rotation recommended

### 4. Monitoring
- ✅ Log all VPN connections
- ✅ Alert on unusual traffic patterns
- ✅ Regular security audits

## Performance

- **Latency Overhead**: <1ms (kernel-native)
- **Throughput**: Near-native (minimal encryption overhead)
- **Concurrent Peers**: 10-20 recommended
- **Keepalive**: 25 seconds (NAT traversal)

## Maintenance

### Add New Client

```bash
./deployment/scripts/generate-client-config.sh new-device-name
```

### Remove Client

```bash
# Edit server config
sudo nano /etc/wireguard/wg0.conf
# Remove [Peer] section

# Reload
sudo systemctl reload wg-quick@wg0
```

### Backup Configuration

```bash
# Backup keys and configs
sudo tar -czf wireguard-backup-$(date +%Y%m%d).tar.gz /etc/wireguard/
```

## Next Steps

- [ ] Deploy WireGuard on server
- [ ] Generate client configs for all devices
- [ ] Test VPN connectivity
- [ ] Verify admin service access
- [ ] Optional: Add minimal CoreDNS for `.internal` domains (Phase 2)

## Support

- **WireGuard Docs**: https://www.wireguard.com/quickstart/
- **nftables Wiki**: https://wiki.nftables.org/
- **Framework Issues**: https://github.com/your-repo/issues