In this tutorial, I will show you how to "spoof" your Media Access Control address or MAC. Some great (and questionable) examples of uses would be allowing yourself onto MAC filtered networks, such as Hotel wifi logins. Please use this method at your own risk, I am not responsible for your actions.

Step 1: What Is a MAC Address?

    A MAC address has nothing to do with Apple or it's computers, but in fact, is part of any device that connects to the internet. The MAC address is assigned to your internet card, and is the one sure-fire way to detect your computer and log it. Well that's the case unless you spoof your MAC address, and becomes anonymous. (this does not mean any of your connections are any more secure, it just means that if someone checks back in their network tables the MAC address of the computer you have will be a fake one).
    The MAC address also identifies who manufactured your computer. So if you spoof it, you can make your computer appear to be a different model, or even appear to be a model of router.
    A MAC address consists of five hexadecimal values (e.g 12-34-56-78-9A-BC). Hexadecimal is a number format used widely by computers and programming languages. Instead of being a base ten number system like the one we are used to, hex works on a base 16 system. And how could that be? Well hex uses letters as well as numbers; 1 through 9 and A through F. For instance, the hex number sequence: 1 2 3 4 5 6 7 8 9 A B C D E F 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D ect...

Step 2: Alright, Down to Tinkering

First of all, you need to fire up a trusty terminal prompt. Now if you aren't familiar with the unix CLI, don't be afraid, terminal is your friend. To learn more about any of the commands you use, just type "man [the command you want help with]" (without quotes and brackets of course). Terminal can be found in the Utilities folder of your Applications. When in doubt, just do a spotlight search.

Step 3: Determining Your MAC Address

Now would be a good time to determine your MAC address, so that you can confirm that it has been changed at the end of the process. To do this simply type in:

ifconfig en1 | grep ether

Which basically means "tell me the configuration of my en1 interface (what you use for wifi if you are on a macbook pro, it could change if you are on a different model, macbooks are usually wlan0) and only show me the lines that deal with my ethernet (the wifi interface)

Step 4: Time for Some ROOT

Now to make the changes necessary for MAC alteration, you need to have root privileges. An easy way of doing this is to change your shell to a superuser shell by entering:

sudo su

It will ask you for your password, but don't be worried, just consider it logging in as root.

Step 5: Let's Change Things Up!

Okay! Now down to what you came here to see. First of all your going to need a MAC address to change to. If you came to this tutorial, I assume you already have one in mind. But you will need a valid one to change to. For the purpose of this example I'll provide one for your experiment: 00:23:6c:90:ff:90
First of all, you need to set up a new wireless utility; Airport. This command is not very well known, but has some cool tricks that come along with it. I encourage any of those who love tinkering around with terminal to view the man page for it, it has some very handy uses.

ln -s /System/Library/PrivateFrameworks/Apple80211.framework/Versions/A/Resources/airport /usr/sbin

This makes a symbolic link to the airport command in your sbin where terminal can see it easily. Next type in:

airport -z

This dissasociates (or disconnects) you from all wireless networks so that you can change your MAC address, sort of like pulling out of gear to change. Next you'll actually change your MAC address. Enter the command:

ifconfig en1 ether XX:XX:XX:XX:XX:XX

And of course replace XX:XX:XX:XX:XX:XX with you desired MAC address. Then you can verify your change with another use of:

ifconfig en1 | grep ether

Once you have verified the change, you can enjoy the benefits of changing your MAC! Thanks for viewing.
<p>Note that on more recent OS X versions, the Airport does not need to disassociate for the new MAC to take effect. That makes things a lot easier. Note that there is also a Cocoa app to achieve the same goal as described in this tutorial: </p><p>https://github.com/halo/LinkLiar</p>
<p>ifconfig: ioctl (SIOCAIFADDR): Device power is off ....</p><p>THIS IS THE INFORMATION I GET AFTER TRY TO CHANGE IT.</p>

About This Instructable




Bio: All of my life I have been interested in learning the way things work. It was always hard for me to use something and just ... More »
More by spel3o:How to Build an 8-Bit Computer Make a Pocket Watch Chain for Your iPod How To Change Your MAC address (Snow Leopard) 
Add instructable to: