Purpose: Provide information and tools for testing and using monitor mode.
Monitor mode, or RFMON (Radio Frequency MONitor) mode, allows a computer with a wireless network interface controller (WNIC) to monitor all traffic received on a wireless channel. Monitor mode allows packets to be captured without having to associate with an access point or ad hoc network first. Monitor mode only applies to wireless networks, while promiscuous mode can be used on both wired and wireless networks. Monitor mode is one of the eight modes that 802.11 wireless cards and adapters can operate in: Master (acting as an access point), Managed (client, also known as station), Ad hoc, Repeater, Mesh, Wi-Fi Direct, TDLS and Monitor mode.
Note: This document and the start-mon.sh script have been tested on the following:
Kali Linux
Raspberry Pi OS
Linux Mint
Ubuntu
sudo apt update
sudo apt full-upgrade
sudo rfkill unblock wlan
sudo apt install aircrack-ng wireshark
iw dev
The wifi interface name wlan0 is used in this document but you will need
to substitute the name of your wifi interface while using this document.
Option 1
sudo airmon-ng check kill
Option 2, another way that works for me on Linux Mint:
Note: I use multiple wifi adapters in my systems and I need to stay connected to the internet while testing. This option works well for me and allows me to stay connected by allowing Network Manager to continue managing interfaces that are not marked as unmanaged.
Ensure Network Manager doesn't cause problems
sudo nano /etc/NetworkManager/NetworkManager.conf
add
[keyfile]
unmanaged-devices=interface-name:<wlan0>;interface-name:wlan0mon
Note: The above tells Network Manager to leave the specified interfaces alone.
Remember to replace <wlan0> with the name of the wifi interface that you
intend to use in monitor mode.
sudo reboot
Option 1
Note: This option may not work with some driver/adapter combinations. If not,
press on with start-mon.sh or option 2.
sudo airmon-ng start <wlan0>
Note: I have provided a script called start-mon.sh to automate most
of the following option. Please give it a try and make suggestions to improve it.
Usage: $ sudo ./start-mon.sh <wlan0>
Option 2
Check the wifi interface name and mode
iw dev
Take the interface down
sudo ip link set <wlan0> down
Set monitor mode
sudo iw <wlan0> set monitor control
Bring the interface up
sudo ip link set <wlan0> up
Verify the mode has changed
iw dev
Option for 5 GHz and 2.4 GHz
sudo airodump-ng <wlan0> --band ag
Option for 5 GHz only
sudo airodump-ng <wlan0> --band a
Option for 2.4 GHz only
sudo airodump-ng <wlan0> --band g
Set the channel of your choice
sudo iw dev <wlan0> set channel <channel> [NOHT|HT20]
sudo aireplay-ng --test <wlan0>
Option for 5 GHz and 2.4 GHz
sudo airodump-ng <wlan0> --band ag
Option for 5 GHz only
sudo airodump-ng <wlan0> --band a
Option for 2.4 GHz only
sudo airodump-ng <wlan0> --band g
sudo airodump-ng <wlan0> --bssid <routerMAC> --channel <channel of router>
Option for 5 GHz:
sudo aireplay-ng --deauth 0 -c <deviceMAC> -a <routerMAC> <wlan0> -D
Option for 2.4 GHz:
sudo aireplay-ng --deauth 0 -c <deviceMAC> -a <routerMAC> <wlan0>
Check the wifi interface name and mode
iw dev
Take the wifi interface down
sudo ip link set <wlan0> down
Set managed mode
sudo iw <wlan0> set type managed
Bring the wifi interface up
sudo ip link set <wlan0> up
Verify the wifi interface name and mode has changed
iw dev
Check the wifi interface name, MAC address and mode
iw dev
Take the wifi interface down
sudo ip link set dev <wlan0> down
Change the MAC address
sudo ip link set dev <wlan0> address <new mac address>
Set monitor mode
sudo iw <wlan0> set monitor control
Bring the wifi interface up
sudo ip link set dev <wlan0> up
Verify the wifi interface name, MAC address and mode has changed
iw dev
sudo iw dev <wlan0> set txpower fixed 1600
Note: 1600 = 16 dBm
The following list describes the currently assigned keys and supported actions:
a
Select active areas by cycling through these display options:
AP+STA; AP+STA+ACK; AP only; STA only
d
Reset sorting to defaults (Power)
i
Invert sorting algorithm
m
Mark the selected AP or cycle through different colors if the selected AP is
already marked
o
Enable colored display of APs and their stations.
p
Disable colored display.
q
Quit program.
r
(De-)Activate realtime sorting -
applies sorting algorithm every time the display will be redrawn
s
Change column to sort by, which currently includes:
BSSID;
PWR level;
Beacons;
Data packets;
Packet rate;
Channel;
Max. data rate;
Encryption;
Strongest Ciphersuite;
Strongest Authentication;
ESSID