Changing MAC address in linux

There are occasions when you may need to change your MAC (Media Access Control) address temporarily. This can be used:
1. While connected to a public wifi hot spot - it keeps your original MAC address anonymous.
2. To bypass a router/switch which has MAC address filtering.
3. To obtain a dhcp ip lease that is allocated based on MAC address.

And remember! MAC address is something that is soldered into your network adapter. You cant change it permanently; in other words, the change that you make is not persistent over reboots.

First let us find out the current MAC address of the Ethernet adapter in my machine

safeer@penguinpower:~$ ifconfig eth0|awk '/HWaddr/{print $1" "$5 }'
eth0 00:13:e4:5c:93:0a

Now I am going to change the MAC address of my Ethernet interface.

First, bring down the interface
safeer@penguinpower:~$ sudo ifconfig eth0 down

Then change the MAC addres to whatever you want
safeer@penguinpower:~$ sudo ifconfig eth0 hw ether 00:22:4d:b7:36:01

Bring up the interface
safeer@penguinpower:~$ sudo ifconfig eth0 up

Verify MAC address has changed.
safeer@penguinpower:~$ ifconfig eth0|awk '/HWaddr/{print $1" "$5 }'
eth0 00:22:4d:b7:36:01

The syntax of the command is "ifconfig [interface name] hw [encapsulation type] [MAC address] "

Every argument is self explanatory except the encapsulation type. This is "ether" (Ethernet) for both our Ethernet and wireless interfaces. For finding out encapsulation type for other interface types see ifconfig man pages. To see the encapsulation type of your network interfaces use the following command

safeer@penguinpower:~$ ifconfig -a|awk '/HWaddr/{split($3,enc,":"); print $1" "enc[2];}'
eth0 Ethernet
wlan0 Ethernet