Address Resolution Protocol is the method for finding a host's link layer (hardware) address when only its Internet Layer (IP) or some other Network Layer address is known. Its main use is primarily to translate IP addresses to Ethernet MAC addresses. The principle of ARP spoofing is to send falsified ARP messages to a target Ethernet LAN. Generally, the aim is to associate the attacker's MAC address with the IP address of another node.Any traffic meant for that IP address would be mistakenly sent to the attacker instead. The attacker could then choose to forward the traffic to the actual default gateway or modify the data before forwarding it. Basically what you are looking for is existence of MAC address cloning, though there are legitimate uses of MAC address cloning. A defense that only works for simple ARP spoofing attacks is the use of static IP-MAC mappings, however, this only prevents some attacks and does not work on a large networks. The key thing to keep in mind is where this attacks originate, which will be from a compromised host, a jack box, or a hacker's machine that is connected directly onto the target Ethernet segment.
