Step-by-step – Realtek Rtl8821AU Kali Driver Installation

Downloading

2. 2. Installing Dependencies

   Then to Install Required Packages
   First, preferably Upgrade your System with:

   sudo apt update && sudo apt upgrade

   In this case then Reboot it using:

   sudo reboot

   Then run:

   sudo apt install build-essential linux-headers-$(uname -r) dkms unzip git

   Authenticate with the User Admin Pass.

3. 3. Downloading Realtek rtl8821AU Driver

   (Bewilderment can arise because this setup is making use of the rtl8812AU Code)
   Download Realtek rtl8821AU Driver in Kali GNU/Linux

   Get Realtek rtl8821AU Driver in Kali

   Realtek rtl8821AU Driver Source Realtek for Kali

   Or better Clone it with Git.
   Especially relevant: in the New Posts Revision I have included a greate Alternative to the default gnab Driver.
   So, in case of the aircrack-ng choice then follow the Github Developer Documentation to setup it.
   Especially relevant: the Aircrack-ng release include support for “Monitor mode” and “Frame injection“!

4. 4. Extracting Realtek rtl8821AU Driver

   And then Extract Driver Archive into /tmp
   (Skip in case of Git Checkout)
   Possibly Double-Click/Right-Click on Package and Open with Archive Manager:

   
   Or from Command Line:

   unzip -d /tmp/ ~/Downloads/*master.zip