Anti-MAC Spoofing Symantec Sygate Enterprise Protection only. An Intrusion Prevention setting that prevents an intruder from taking advantage of the ability to forge (or spoof) a Media Access Control (MAC) address of a computer. Anti-MAC Spoofing allows incoming and outgoing ARP (Address Resolution Protocol) traffic only if an ARP request has been made to a specific host. It blocks all other unexpected ARP traffic and logs it in a Security Log. See also Smart ARP, MAC address, MAC Spoofing.