# Add VLAN 11 Secondary IP Address - Guide

**Last Updated:** 2026-01-15  
**Status:** Active Documentation
**Purpose:** Configure machine to have both current IP and VLAN 11 IP

---

## Current Configuration

- **Primary Interface:** eth0
- **Current IP:** 192.168.0.4/24
- **Current Gateway:** 192.168.0.1
- **Target VLAN 11 IP:** 192.168.11.4/24
- **VLAN 11 Gateway:** 192.168.11.1

---

## Option 1: Temporary Configuration (Until Reboot)

**Quick Setup:**
```bash
sudo ./scripts/unifi/add-vlan11-secondary-ip.sh
```

**Manual Commands:**
```bash
# Add secondary IP
sudo ip addr add 192.168.11.4/24 dev eth0

# Add route to VLAN 11 network
sudo ip route add 192.168.11.0/24 dev eth0 src 192.168.11.4

# Verify
ip addr show eth0 | grep "inet "
```

**Test Connectivity:**
```bash
ping -c 3 192.168.11.1   # VLAN 11 gateway
ping -c 3 192.168.11.10  # ml110
ping -c 3 192.168.11.11  # r630-01
ping -c 3 192.168.11.12  # r630-02
```

---

## Option 2: Persistent Configuration (Survives Reboot)

### Option 2a: Using ifupdown (if /etc/network/interfaces exists)

```bash
sudo ./scripts/unifi/add-vlan11-secondary-ip-ifupdown.sh
```

**Manual ifupdown Configuration:**

1. **Edit /etc/network/interfaces:**
   ```bash
   sudo nano /etc/network/interfaces
   ```

2. **Add VLAN 11 alias interface:**
   ```
   # VLAN 11 secondary IP address
   auto eth0:11
   iface eth0:11 inet static
       address 192.168.11.4
       netmask 255.255.255.0
       gateway 192.168.11.1
   ```

3. **Apply configuration:**
   ```bash
   sudo ifdown eth0:11 2>/dev/null || true
   sudo ifup eth0:11
   ```

### Option 2b: Using Netplan (if netplan is installed)

```bash
sudo ./scripts/unifi/add-vlan11-secondary-ip-netplan.sh
```

**Manual Netplan Configuration:**

1. **Find netplan config:**
   ```bash
   ls /etc/netplan/*.yaml
   ```

2. **Edit the config file:**
   ```bash
   sudo nano /etc/netplan/*.yaml
   ```

3. **Add VLAN 11 IP to eth0:**
   ```yaml
   network:
     version: 2
     renderer: networkd
     ethernets:
       eth0:
         addresses:
           - 192.168.0.4/24      # Current IP
           - 192.168.11.4/24     # VLAN 11 IP (add this)
         gateway4: 192.168.0.1   # Current gateway
         routes:
           - to: 192.168.11.0/24
             via: 192.168.11.1
         nameservers:
           addresses:
             - 192.168.0.1
             - 8.8.8.8
   ```

4. **Apply configuration:**
   ```bash
   sudo netplan try
   sudo netplan apply
   ```

5. **Verify:**
   ```bash
   ip addr show eth0 | grep "inet "
   ```

---

## Verification

After configuration, verify:

```bash
# Check IP addresses
ip addr show eth0 | grep "inet "

# Should show:
# inet 192.168.0.4/24 ... (current IP)
# inet 192.168.11.4/24 ... (VLAN 11 IP)

# Test connectivity
ping -c 3 192.168.11.1   # VLAN 11 gateway
ping -c 3 192.168.11.10  # ml110
ping -c 3 192.168.0.1    # Default gateway (should still work)
```

---

## Benefits

With both IPs configured:

1. **Access to Default Network:**
   - Can access UDM Pro (192.168.0.1)
   - Can access devices on 192.168.0.0/24

2. **Access to VLAN 11:**
   - Can access Proxmox hosts (192.168.11.10-12)
   - Can access services on VLAN 11
   - Can manage VLAN 11 resources

3. **Dual Network Access:**
   - Best of both worlds
   - No need to switch networks
   - Can access both simultaneously

---

## Troubleshooting

### Issue: Cannot ping VLAN 11 gateway

**Possible Causes:**
1. VLAN 11 gateway not configured on UDM Pro
2. Network Isolation enabled
3. Firewall blocking

**Solutions:**
1. Verify UDM Pro VLAN 11 configuration
2. Check Network Isolation settings
3. Verify firewall rules

### Issue: IP address not persistent after reboot

**Solution:** Use netplan configuration (Option 2)

### Issue: Route conflicts

**Solution:** Check existing routes:
```bash
ip route show
```

Remove conflicting routes if needed:
```bash
sudo ip route del 192.168.11.0/24
```

---

## Summary

**Status:** ✅ Scripts ready

**Quick Start:**
```bash
# Temporary (until reboot)
sudo ./scripts/unifi/add-vlan11-secondary-ip.sh

# Persistent (survives reboot)
sudo ./scripts/unifi/add-vlan11-secondary-ip-netplan.sh
```

**Result:**
- ✅ Keep current IP: 192.168.0.4
- ✅ Add VLAN 11 IP: 192.168.11.4
- ✅ Access both networks simultaneously

---

**Last Updated:** 2026-01-15