MacMakeup is a freeware program that allows you to spoof your MAC address.
To spoof your MAC address, you need to: 1. Select your network interface 2. Type the new MAC address into the box 3. Click "Spoof"
Done! You need to disable and enable the interface again.
If the MAC address is already spoofed on an interface, you can use the "Reset to original" button to go back to your original one.
Starting from 2.1.x the distribution zip contains an oui.txt file. The file is a stripped version of the one you can download here. This file is a sort of database that maps the first 24 bits of the MAC address to a manufacturer. For example, if you see a MAC starting with 00A03F, you can assume it is from a device that was made by Apple. This if there were no spoofed MAC addresses of course.
Loading (and working) with the OUI database is not mandatory and can slow down the program, so load them if needed by pressing "Load OUIs."
With the database loaded you can select a manufacturer from the list, and a new MAC address from that vendor will be proposed in the MAC address box. Also if you choose an interface with a spoofed MAC, the presumed vendor will be displayed in the information area.
You can type part of the name of the desired vendor in the box to filter the database.
If you do not need all of the (about) 30000 manufacturers, you can reduce the file to the bunch you use the most and delete the lines you don't need. Keep in mind that only the lines containing "base 16" are needed. You can easily update the file running: