Fix Alfa WiFi Adapter Not Detected in Kali Linux (Realtek RTL88xxAU / RTL8814AU Driver)

You’ve just picked up a brand new wireless adapter and fired up Kali Linux, ready to dive into some Wi-Fi hacking. You run iwconfig to check your interfaces, expecting to see wlan0... but it's not there.

This is a common problem for newcomers and veterans alike. Fortunately, it’s fixable. In this post, I’ll walk you through the steps I use to get USB Wi-Fi adapters working inside a Kali Linux virtual machine. The tutorial focuses on the ALFA AWUS1900 but applies broadly to many adapters using Realtek chipsets.

Disclaimer: This guide is for educational purposes only. Always ensure you have legal permission before conducting any form of wireless testing.

Related Video:

Step 1: Plug in the Adapter

Start by physically plugging your USB Wi-Fi adapter into your machine. If you’re using VMware, you should see a pop-up asking whether to connect the device to the host or the VM. The goal is to connect the adapter to Kali, not your host machine.

If the OK button is grayed out in the pop-up, don’t worry. Connect it to the host first, then go to the top menu bar, right-click the VM name, select Removable Devices, find your adapter (e.g., Realtek 802.11ac NIC), and click Connect (Disconnect from Host).

Step 2: Check with lsusb

To verify the adapter is recognized by the VM, run:

lsusb

You should see your wireless adapter listed. If you don’t, the device isn’t connected properly, and you’ll need to troubleshoot the connection in your hypervisor settings.

Step 3: Check for wlan0 with iwconfig

Now run:

iwconfig

If wlan0 still isn’t showing, even though the adapter is detected by lsusb, the issue likely lies with missing drivers or mismatched kernel headers.

Step 4: Update Kali and Install Required Packages

First, update your Kali Linux repositories:

sudo apt update

Then install the necessary Realtek drivers and kernel headers. Replace <driver-name> with the appropriate driver name for your adapter (commonly realtek-rtl88xxau-dkms or similar):

sudo apt install realtek-rtl88xxau-dkms linux-headers-amd64

This step can take several minutes. Press Y to confirm the installation when prompted.

Step 5: Check for Kernel Mismatch

Even after installing drivers and headers, wlan0 may still not show up. The problem often lies in a kernel mismatch; your running kernel and the installed headers don’t match.

Check your kernel version:

uname -r

Then check which headers are installed:

apt policy linux-headers-amd64

If these versions don’t match, the DKMS module can’t be properly built, and your wireless interface won’t be registered.

Step 6: Fix the Kernel/Header Mismatch

To fix this, you have two options:

Option A: Automatically Match with uname -r

sudo apt install linux-headers-$(uname -r)

Option B: Specify Header Version Manually

If you know the version you need, you can install it explicitly:

sudo apt install linux-headers-6.12.13

(Replace with your actual kernel version.)

Step 7: Reboot into the Correct Kernel

If the header version you installed doesn’t match your current kernel, you’ll need to reboot into the correct one.

1. Click the power icon in the top right and select Restart.

2. During boot, quickly select Advanced options for Kali.

3. Choose the kernel version that matches the headers you installed.

4. Boot into that version.

   
   

After booting, confirm your kernel with:

uname -r

Then check for wlan0 again:

iwconfig

If all went well, your wireless interface should now be available.

Step 8: Make the Kernel Selection Permanent

To avoid having to manually select your kernel on every boot, update GRUB to remember your last boot choice:

sudo nano /etc/default/grub

Add this line at the top or anywhere in the file:

GRUB_SAVEDEFAULT=true

Then run:

sudo update-grub

From now on, Kali will remember and boot into your last-selected kernel version by default.

Summary

If you're not seeing wlan0 in Kali Linux, it's rarely the adapter's fault. The issue typically comes down to a mismatch between your kernel and the installed headers. By identifying the mismatch and fixing it (either by installing the correct headers or switching kernels), you can get your wireless adapter up and running without replacing hardware.

Here’s a quick recap:

• Use lsusb to confirm the adapter is recognized.

• Install the correct drivers and kernel headers.

• Use uname -r and apt policy to detect mismatches.

• Match kernel and headers by installing the right version.

• Reboot into the matching kernel.

• Update GRUB to make your fix persistent.

Now you’re back in action, ready to explore wireless attacks and ethical hacking labs.