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.
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:
sudo apt remove dnsmasq-base
Disable the default network to avoid collisions:
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:
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:
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:
lsusb
You should see something like:
Bus 001 Device 002: ID 0bda:b812 Realtek Semiconductor Corp. RTL88x2bu
Attach it to your VM:
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:
sudo apt update
sudo apt install -y hostapd dnsmasq nftables iw
Enable hostapd to start on boot:
sudo systemctl unmask hostapd
sudo systemctl enable hostapd
Create the configuration file:
sudo nano /etc/hostapd/hostapd.conf
Paste the following (adjust SSID and password as needed):
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:
sudo nano /etc/default/hostapd
Set:
DAEMON_CONF="/etc/hostapd/hostapd.conf"
Edit the dnsmasq configuration:
sudo nano /etc/dnsmasq.conf
Add:
interface=wlx80afcaa8d523
dhcp-range=192.168.99.10,192.168.99.100,12h
Then restart:
sudo systemctl restart dnsmasq
🔀 8. Enable IP Forwarding
sudo nano /etc/sysctl.conf
Uncomment or add:
net.ipv4.ip_forward=1
Apply:
sudo sysctl -p
🔒 9. Set Up NAT with nftables
Create your NAT rules:
sudo nano /etc/nftables.conf
Insert:
table inet nat {
chain postrouting {
type nat hook postrouting priority 100;
oifname "enp1s0" masquerade
}
}
Apply and enable:
sudo nft -f /etc/nftables.conf
sudo systemctl enable nftables
🚀 10. Start the Access Point
sudo systemctl start hostapd
Check the status:
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! 💬🛜
