Patent ID: 8302190

Claim:
A method for defending against Address Resolution Protocol (ARP) spoofing attacks implemented by a network device, comprising: setting an update flag in an ARP entry, wherein the ARP entry comprises an Internet Protocol (IP) address, a master Media Access Control (MAC) address, a temporary MAC address and the update flag; the update flag indicating whether the master MAC address and the temporary MAC address of the ARP entry can be updated before the ARP entry is aged; receiving an ARP message which has the same IP address as the ARP entry; when the update flag has a first value indicating that the ARP entry is updatable, judging whether an MAC address in the received ARP message is the same as the master MAC address in the ARP entry; if the MAC address in the received ARP message is different from the master MAC address, updating the temporary MAC address of the ARP entry according to the MAC address in the received ARP message; setting the update flag to a second value which indicates that the ARP entry is not updated before an ARP verification response is received; and starting an ARP verification process.