According to an embodiment of the present invention, an SDN controller for solving an ARP poisoning attack in an SDN network includes: a memory storing an ARP table management program; a data input/output module inputting and outputting data; and a processor executing the ARP table management program stored in the memory. The ARP table management program matches a MAC address included in an ARP response message received in response to an ARP request message of a client with a destination IP address included in the ARP request message and stores the matched address in an ARP table through the processor while activating a timer if a new MAC address included in the ARP response message is different from an existing MAC address pre-stored in the ARP table, and determines an ARP response message including the new MAC address as an ARP poisoning attack if the ARP response message is re-received before the termination of the timer, and then, maintains the storage of the existing MAC address on the ARP table.
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