# 🛠️ Adding a Wi-Fi Access Point to Your SD-WAN Edge Using the Cudy WU1400

As more SD-WAN edge devices are being deployed in remote and field environments, adding wireless access directly to the edge becomes a compelling use case. Whether you're trying to provide AP functionality for engineers on site, local devices, or simply as a backup access path—this guide is your one-stop resource for turning a **Cudy WU1400 USB adapter** into a full-fledged **Access Point (AP)** using **Debian Bookworm**.

---

## 📦 1. Prepare Your Virtualisation Environment

Before creating your NFV instance, make sure your Debian host system has **libvirt** and related packages installed.

```plaintext
sudo apt update
sudo apt upgrade
sudo apt install -y qemu-kvm libvirt-daemon-system libvirt-clients virtinst cpu-checker libguestfs-tools libosinfo-bin
```

Then remove the conflicting `dnsmasq-base` package:

```plaintext
sudo apt remove dnsmasq-base
```

Disable the default network to avoid collisions:

```plaintext
sudo virsh net-autostart --disable default
```

---

## 🐧 2. Install Debian Bookworm as a Headless NFV

Create a virtual machine using `virt-install`. You’ll be installing Debian Bookworm directly via the serial console:

```plaintext
sudo virt-install \
  --name debian \
  --ram 1024 \
  --vcpus 1 \
  --disk path=/var/lib/libvirt/images/debian12.qcow2,size=4 \
  --os-variant debian10 \
  --network bridge=br0,model=virtio \
  --console pty,target_type=serial \
  --extra-args="console=ttyS0,115200n8" \
  --graphics none \
  --location 'http://deb.debian.org/debian/dists/bookworm/main/installer-amd64/'
```

📝 **Note:** Make sure you’re using a bridge (`br0`) that has Internet access.

---

## 📥 3. Update Kernel & Install Firmware

Once Debian is installed and running:

```plaintext
sudo apt install -t bookworm-backports linux-image-amd64
sudo apt install firmware-realtek
```

This ensures proper driver support for your Cudy USB adapter (based on Realtek RTL88x2BU chipset).

---

## 🔌 4. Attach the Cudy WU1400 to the NFV

Plug the Wi-Fi dongle into your host and identify it using:

```plaintext
lsusb
```

You should see something like:

```plaintext
Bus 001 Device 002: ID 0bda:b812 Realtek Semiconductor Corp. RTL88x2bu
```

Attach it to your VM:

```plaintext
virsh attach-device debian --file <(cat <<EOF
<hostdev mode='subsystem' type='usb' managed='yes'>
  <source>
    <vendor id='0x0bda'/>
    <product id='0xb812'/>
  </source>
</hostdev>
EOF
)
```

---

## 📡 5. Install Required Software Inside the VM

Once the device is visible inside your VM (`lsusb` inside the guest should show it), install:

```plaintext
sudo apt update
sudo apt install -y hostapd dnsmasq nftables iw
```

Enable `hostapd` to start on boot:

```plaintext
sudo systemctl unmask hostapd
sudo systemctl enable hostapd
```

---

## ⚙️ 6. Configure hostapd (Wi-Fi AP)

Create the configuration file:

```plaintext
sudo nano /etc/hostapd/hostapd.conf
```

Paste the following (adjust SSID and password as needed):

```plaintext
interface=wlx80afcaa8d523
driver=nl80211
ssid=debian
hw_mode=a
channel=36
ieee80211d=1
country_code=ZA
ieee80211n=1
ht_capab=[HT40+][SHORT-GI-20][SHORT-GI-40]
ieee80211ac=1
vht_capab=[SHORT-GI-80]
wmm_enabled=1
auth_algs=1
wpa=2
wpa_passphrase=0836457154
wpa_key_mgmt=WPA-PSK
rsn_pairwise=CCMP
```

Then point `hostapd` to the config:

```plaintext
sudo nano /etc/default/hostapd
```

Set:

```plaintext
DAEMON_CONF="/etc/hostapd/hostapd.conf"
```

---

## 📡 7. Configure dnsmasq for DHCP

Edit the dnsmasq configuration:

```plaintext
sudo nano /etc/dnsmasq.conf
```

Add:

```plaintext
interface=wlx80afcaa8d523
dhcp-range=192.168.99.10,192.168.99.100,12h
```

Then restart:

```plaintext
sudo systemctl restart dnsmasq
```

---

## 🔀 8. Enable IP Forwarding

```plaintext
sudo nano /etc/sysctl.conf
```

Uncomment or add:

```plaintext
net.ipv4.ip_forward=1
```

Apply:

```plaintext
sudo sysctl -p
```

---

## 🔒 9. Set Up NAT with nftables

Create your NAT rules:

```plaintext
sudo nano /etc/nftables.conf
```

Insert:

```plaintext
table inet nat {
    chain postrouting {
        type nat hook postrouting priority 100;
        oifname "enp1s0" masquerade
    }
}
```

Apply and enable:

```plaintext
sudo nft -f /etc/nftables.conf
sudo systemctl enable nftables
```

---

## 🚀 10. Start the Access Point

```plaintext
sudo systemctl start hostapd
```

Check the status:

```plaintext
sudo systemctl status hostapd
```

---

## 🧪 11. Test Your SD-WAN Edge AP

* Scan for `SSID: debian` from a nearby device 📱
    
* Connect using the password `0836457154` 🔐
    
* Test Internet connectivity 🌐
    

---

## 🧠 Why Add an AP to SD-WAN?

✅ Local Wi-Fi for on-site teams  
✅ Backup access to SD-WAN interface  
✅ Enables IoT or mobile device integration  
✅ Useful in remote setups like kiosks or retail edge sites

---

## 🧩 Final Notes

💡 The Cudy WU1400 is a great, compact, and affordable USB adapter with support for **802.11ac (Wi-Fi 5)**.  
📡 It transforms your NFV or SD-WAN edge into a **connectivity hub** with a few simple steps.  
🔧 Everything is standard Debian—no vendor lock-in, no proprietary tools.

---

Need help troubleshooting or integrating with your SD-WAN platform? Drop your questions below, and let's level up your edge connectivity game! 💬🛜