(Last Updated On: December 11, 2018)

There are situations that you must change or spoof your MAC address of your Network Interface Card.The reasons for Changing can be controversial. For example,when performing some authorised security audits, it may be necessary to  change your MAC address while MAC filtering  is ON. Also, an attacker may have gained access to your machine illegally and wants to leave no trace of his activity and what he will do is use a fake MAC address when attacking your system so that you cannot trace him/her back. To Mitigate MAC spoofing techniques, you have to know how to spoof it yourself. Lets get started.

We will consider two situations; changing your MAC address temporarily and Making the address permanent.
For this Tutorial we’ll use Kali Linux,which by default comes with macchanger.There is a tutorial on Top Ten Must Do Things After Installing Kali Linux .Macchanger  is a Linux utility for viewing/manipulating the MAC address for network interfaces. If you are running a different distribution Of Linux, you may have to install macchanger, you will need superuser privileges to install it using sudo command.
 How to install macchanger in Debian based distributions and Ubuntu

 sudo apt-get install macchanger

  How to install macchanger in Redhat, Fedora, Centos, RHEL

 sudo yum install macchanger

To change MAC address with Macchanger type:

 sudo macchanger --mac=XX:XX:XX:XX:XX:XX

 OR:

 sudo macchanger -m=XX:XX:XX:XX:XX:XX

Replace xx:xx:xx:xx:xx:xx with your desired spoofed MAC address.

Other options used with Macchanger are:

   -h, –help
Show summary of options.

-V, –version
Show version of program.

  -e, –ending
Don’t change the vendor bytes.

  -a, –another
Set random vendor MAC of the same kind.

-A     Set random vendor MAC of any kind.

-r, –random
Set fully random MAC.

-p, –permanent
Reset MAC address to its original, permanent hardware value.

       -l, –list[=keyword]
Print known vendors (with keyword in  the  vendor’s  description

To change your MAC address without the macchanger program using ifconfig Command. Follow the steps below
1. Take a note of your original MAC address

2. Take the interface you wanna change the MAC address down

sudo ifdown eth0 for ethernet 0 interface and

sudo ifdown wlan0 for wireless interface.

3. Next step is to configure new MAC address, this will be temporary and will be lost when you restart your machine.

sudo ifconfig eth0 hw ether 11:22:03:02:ab:bb
sudo ifconfig wlan0 hw ether 11:22:03:02:ab:bb

My new MAC will be 11:22:03:02:ab:bb. Rem it is hexadecimal 48 bits long.

4. Return your interface up 
 To bring eth0 interface up type:

sudo ifup eth0

To bring wlan0 interface up type the following command.

 sudo ifup wlan0  

To make a spoofed MAC address permanent,open interfaces file

 sudo vi /etc/network/interfaces

For RedHat based distros it will be located in /etc/sysconfig/network-scripts directory.Also check How To Configure a Static IP Address on CentOS 7.0 and 6.5
Add the following line 
For eth0 interface, add:

 pre-up ifconfig eth0 hw ether 11:22:03:02:ab:bb 

For wlan0 interce add:

 pre-up ifconfig wlan0 hw ether 11:22:03:02:ab:bb

Save the changes and quit, then restart yout Network Interface.
See How To Install Conky manager in Kali Linux and Ubuntu, it is a nice way to See your system resources usage graphically.