Nmap
From Hackepedia
If you don't find an option in your version of nmap, you might want to upgrade to the latest version. We were using nmap 4.20 for the purposes of this page.
You may wish to spoof your MAC address. You can specify 0 for random, or the name of a vendor such as "Cisco", or the actual MAC address you want to impersonate:
--spoof-mac Cisco