Patent ID: 7516487

Claim:
A network device providing switching functionality for use in a computer network having a plurality of hosts, each host having a MAC address, the network device comprising: a plurality of ports; a table for storing source IP address and MAC address pairs for data packets received on the plurality of ports; and a processor operable to: determine a number of unsuccessful validation attempts for one or more new source IP addresses received over a given time period, wherein the one or more new source IP addresses correspond to source IP addresses that are not stored in the table; compare the number of unsuccessful validation attempts with a threshold number of unsuccessful validation attempts; if the number of unsuccessful validation attempts is less than the threshold number, cause the network device to operate in a first mode, wherein in the first mode validation is performed on data packets received from new source IP addresses after the given time period; if the number of unsuccessful validation attempts is greater than the threshold number, cause the network device to operate in a second mode, wherein in the second mode data packets received from new source IP addresses after the given time period are dropped without validation; identify a MAC address of a host coupled to a port in the plurality of ports; learn and verify a source IP address associated with the MAC address; store the source IP address and the MAC address in the table; and after storing the source IP address and the MAC address, apply a group of rules for forwarding a data packet received on the port if the data packet has the MAC address and the source IP address.