3. Change MAC address in Linux
In this practical we changed the MAC address on a Kali Linux system. A MAC (Media Access Control) address is a unique identifier assigned to a network interface card (NIC). Changing it can be useful for privacy or testing purposes. Following are the steps:
Step 1: Identify the Network Interface
Open the terminal and list the available network interfaces using:
ifconfig

Alternatively, use:
ip link show
From the output, identify the interface you want to change the MAC address for. In this example, the active interface is eth0
with the current MAC address: 00:0c:29:cc:99:31
.
Step 2: Bring Down the Network Interface
Before changing the MAC address, disable the interface temporarily. Use the following command:
sudo ifconfig eth0 down
Replace eth0
with the name of your network interface (from Step 1).
Step 3: Change the MAC Address
Assign a new MAC address to the interface. Use the command:
sudo ifconfig eth0 hw ether 12:34:56:78:9A:BC
Replace 12:34:56:78:9A:BC
with the desired MAC address. Alternatively, you can randomize the MAC address using the macchanger
tool:
sudo apt install macchanger # Install macchanger if not already installed
sudo macchanger -r eth0 # Randomize the MAC address
Step 4: Bring Up the Network Interface
Re-enable the network interface using:
sudo ifconfig eth0 up
Step 5: Verify the New MAC Address
Confirm that the MAC address has been successfully updated by running:
ifconfig eth0
Look for the ether
field in the output. It should show the new MAC address.

Optional: Persistent MAC Address Change
By default, the MAC address change is temporary and will reset after a reboot. To make it permanent, edit the network configuration file:
sudo nano /etc/network/interfaces
Add the following lines for the network interface:
iface eth0 inet dhcp
hwaddress ether 12:34:56:78:9A:BC
Save and exit the editor (press Ctrl+O
, then Enter
, and Ctrl+X
). Restart the network service:
sudo systemctl restart networking
Notes:
- Use a valid and unique MAC address to avoid conflicts.
- Some networks may reject a changed MAC address. Use this feature responsibly.
- Administrative privileges are required for these steps (use
sudo
).