Figure out which
en interface to use
See the mac address
ifconfig en0 | grep ether
The arp utility displays and modifies the Internet-to-Ethernet address translation tables used by the address resolution protocol (arp(4)). With no flags, the program displays the current ARP entry for hostname. The host may be specified by name or by number, using Internet dot nota-tion.
Display current ARP entries.
Disconnect from current wifi network (if connected). Do not turn OFF wifi — the MAC address may reset when you turn it back on.
sudo /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/[PUBLICWIFI] -z
Change your MAC address to a different one
sudo ifconfig en0 ether [new mac address]