Issue in Monitor mode

[Brainless-Guy]

Linux detects the driver well, but the ac600 adapter fails to detect any network in monitor mode

as you said , I didn't use the driver as its kernerl version 14+ , but should I use it? my monitor mode is not working.

and yes I am dumb ( if i am doing anything dumb)

[morrownr]

What is the result of:

sudo iw dev

[Brainless-Guy]

sorry for extremely late response,

here is the output :

In Manged Mode:

phy#1
        Interface wlan0
                ifindex 3
                wdev 0x100000001
                addr 9e:1a:43:37:d4:af
                type managed
                txpower 20.00 dBm
                multicast TXQ:
                        qsz-byt qsz-pkt flows   drops   marks   overlmt hashcol tx-bytes        tx-packets
                        0       0       0       0       0       0       0       0               0

in monitor mode:

phy#0
        Interface wlan0
                ifindex 3
                wdev 0x1
                addr 8c:90:2d:ca:b4:bd
                type monitor
                channel 10 (2457 MHz), width: 20 MHz (no HT), center1: 2457 MHz
                txpower 20.00 dBm
                multicast TXQ:
                        qsz-byt qsz-pkt flows   drops   marks   overlmt hashcol tx-bytes        tx-packets
                        0       0       0       0       0       0       0       0               0

and wlan0 doesnt change to wlan0mon.

[morrownr]

@Brainless-Guy

Okay, thanks for running the command. I see you are able to enter monitor mode. Now to go over the details.

I didn't use the driver as its kernerl version 14+ , but should I use it? my monitor mode is not working.

Don't say monitor mode is not working. You haven't shown me anything yet that tells me it is not working. Let's dig in.

I need you to clarify a few things:

I need to make sure what chip is in your adapter. Run and post the results of:

lsusb

Give me some details of your system such as distro, distro version and exact kernel.

Tell me what monitor mode tools that you are using.

Tell me what you are trying to do.

[Brainless-Guy]

Okay...

Out put of lsusb:

Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 002: ID 80ee:0021 VirtualBox USB Tablet
Bus 001 Device 004: ID 2357:0120 TP-Link Archer T2U PLUS [RTL8821AU]

Output of uname -a

Linux kali 6.18.5+kali-amd64 #1 SMP PREEMPT_DYNAMIC Kali 6.18.5-1kali1 (2026-01-19) x86_64 GNU/Linux

I also tried Arch, But didn't seem to function properly. ( i think)

I tried airmon-ng, and also did Manually.

sudo ifconfig wlan0 down
sudo iwconfig wlan0 mode monitor
sudo ifconfig wlan0 up

and I am using Virtualbox

and I am using it to monitor traffic.

[morrownr]

@akmalkadi

Your output of lsusb confirms that the adapter is based on the rtl8821/11au chip.

Let's check to make sure what driver you are using:

$ lsmod | grep 8821

Output of uname -a

The driver in kernel 6.18 is good. There are a couple of limitations that apply to some situations but with the knowledge of what to avoid, you should get along fine:

• No Realtek WiFi 5 drivers, whether the old out-of-kernel variety or the new in-kernel drivers, supports virtual interface (VIF). It is a capability that Realtek has not supported and it will likely never be supported.

• There is a mode within monitor mode called active monitor mode. A few things needs this but it is not supported in Realtek WiFi 5 adapters.

I tried airmon-ng, and also did Manually.

I have a script called start-mon-sh that will help you get into monitor mode and it does a much better job with processes that may interfere. Recommend that you try it:

https://github.com/morrownr/Monitor_Mode

channel 10 (2457 MHz), width: 20 MHz (no HT), center1: 2457 MHz

You need to set the channel you want to work with and channel 10 would be an unusua channel for an ap to be set to. My script asks you to set the channel.

and I am using it to monitor traffic.

Have you considered using wireshark?

and I am using Virtualbox

I have a guide around here somewhere about using Virtualbox. I can find it if you need it.