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ALFA Adapters on Ubuntu — Complete Setup Guide

學習目標（Learning goal）: By the end of this guide you will have your ALFA adapter visible in Ubuntu (iw dev), connected to Wi-Fi, and — for the supported chipsets — able to switch into monitor mode. 適用對象: Beginner–intermediate ｜ 前置需求: Ubuntu 20.04+ (22.04+ for Wi-Fi 6E models), an internet connection (you need it to install packages!), and your ALFA adapter.

Concept: two kinds of drivers​

Before touching the terminal, understand why the setup differs between adapters. There are two worlds:

  1. In-kernel chipsets (MediaTek) — the driver is already compiled into Ubuntu. Plug in → works. This covers the MT7612U (AWUS036ACM), MT7610U (AWUS036ACHM), and MT7921AUN (AWUS036AXM / AWUS036AXML, needs Ubuntu 22.04+ / kernel 5.18+).
  2. DKMS chipsets (Realtek) — the driver is not in the kernel, so you compile it once, and DKMS keeps it rebuilt after every kernel update. This covers the RTL8812AU (AWUS036ACH), RTL8811AU (AWUS036ACS), and RTL8832BU (AWUS036AX / AWUS036AXER).

Prerequisites​

  • Ubuntu 20.04 or newer (check with lsb_release -a)
  • Working internet (Wi-Fi or Ethernet) to download packages
  • Your ALFA adapter and a USB-A or USB-C cable (AXML uses USB-C)
  • sudo access

Step 1: Identify your chipset​

Plug the adapter in, then ask Ubuntu what it sees:

lsusb

Expected output (look for the MediaTek / Realtek line):

Bus 001 Device 004: ID 0e8d:7612 MediaTek Inc. MT7612U 802.11a/b/g/n/ac 2T2R Wireless Adapter
Bus 001 Device 005: ID 0bda:8812 Realtek Semiconductor Corp. RTL8812AU 802.11a/b/g/n/ac 2T2R Wireless Adapter
  • 0e8d = MediaTek (in-kernel path)
  • 0bda = Realtek (DKMS path)
  • Not sure? Cross-check the chipset table in the compatibility matrix.

Step 2: The in-kernel path (MediaTek — plug and play)​

If your adapter uses a MediaTek chipset, nothing to install. Verify:

iw dev

Expected output:

phy#0
	Interface wlan0
		ifindex 3
		addr 00:c0:ca:xx:xx:xx
		type managed

See wlan0? Congratulations — the driver is live. Connect via the desktop Wi-Fi menu or NetworkManager:

nmcli device wifi connect "MySSID" password "my-passphrase"

Expected output: Device 'wlan0' successfully activated with 'MySSID'.

Skip ahead to Step 4: verify.

Step 3: The DKMS path (Realtek — one-time build)​

For the RTL8812AU (AWUS036ACH), RTL8811AU (AWUS036ACS) and RTL8832BU (AWUS036AX / AXER), build the driver once. All three follow the same pattern — install tools, clone the repo, run the installer.

3.1 Install the build tools​

sudo apt update
sudo apt install -y build-essential dkms git

Expected output: ends with Setting up dkms ... and no errors. DKMS is the piece that will recompile the driver after kernel updates.

3.2 RTL8812AU (AWUS036ACH)​

The most battle-tested repo is maintained by the aircrack-ng project:

cd /opt
sudo git clone https://github.com/aircrack-ng/rtl8812au.git
cd rtl8812au
sudo make dkms_install

Expected output:

DKMS: install completed.

The module is now 8812au and DKMS will rebuild it on every kernel update — you can forget it exists.

3.3 RTL8811AU (AWUS036ACS)​

cd /opt
sudo git clone https://github.com/aircrack-ng/rtl8811au.git
cd rtl8811au
sudo make dkms_install

Expected output: DKMS: install completed. — module name 8811au.

3.4 RTL8832BU (AWUS036AX / AWUS036AXER)​

cd /opt
sudo git clone https://github.com/aircrack-ng/rtl88x2bu.git
cd rtl88x2bu
sudo make dkms_install

Expected output: DKMS: install completed. — module name 88x2bu.

3.5 Re-plug and check​

Unplug and re-plug the adapter (or run sudo modprobe <module>), then verify:

iw dev

Expected output: an Interface wlan1 (or wlan0 if it is your only adapter) line appears.

You might be wondering — "Which module name corresponds to my adapter?" Match your chipset: 8812au → AWUS036ACH, 8811au → AWUS036ACS, 88x2bu → AWUS036AX / AXER. The driver pages have deeper per-chipset details.

Step 4: Verify everything​

A three-command health check:

ip link show | grep -E "^[0-9]+: wl"        # interface exists?
iw dev                                       # interface + phy info
iw reg get | head -20                        # regulatory domain (affects power/channels)

Expected output:

3: wlan1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP
phy#1
	Interface wlan1
		ifindex 3
		addr 00:c0:ca:xx:xx:xx
		type managed

All three commands producing output = your ALFA adapter is fully operational.

Advanced: monitor mode (supported chipsets)​

Monitor mode lets the adapter capture every packet on a channel instead of only its own connection. On the in-kernel chipsets this is a two-command job:

sudo ip link set wlan1 down
sudo iw wlan1 set monitor none
sudo ip link set wlan1 up
iw dev

Expected output: type monitor instead of type managed.

⚠️ Important: type managed (the default) means the driver filters everything not addressed to you. type monitor disables that filter — a huge amount of traffic suddenly becomes visible. Only run this on networks you own or have explicit permission to test. See the Kali guide for the full packet-injection workflow.

Common errors (FAQ)​

Error / symptomCauseFix
lsusb shows the adapter but no wlanX interfaceDKMS module not loaded (Realtek)sudo modprobe 8812au (match your chipset), then check dmesg | tail
make dkms_install fails with "Kernel preparation unnecessary"Missing kernel headerssudo apt install linux-headers-$(uname -r) and retry
Adapter disappears after apt upgradeKernel updated, DKMS rebuild failed silentlysudo dkms autoinstall then reboot
iw dev shows nothing after reboot (Realtek)Module not in auto-load listecho 8812au | sudo tee /etc/modules-load.d/alfa.conf
Wi-Fi 6E adapter (AXML) not detected on 20.04Kernel too old for mt7921uUpgrade to Ubuntu 22.04+ (kernel 5.18+)

References​