METHOD FOR PREVENTING ARP/IP SPOOFING AUTOMATICALLY ON THE DYNAMIC IP ADDRESS ALLOCATING ENVIRONMENT USING DHCP PACKET

摘要

PURPOSE: A method for preventing automatically ARP/IP spoofing is provided to reduce damage due to an ARP/IP spoofing attack and enhance security by monitoring IP addresses assigned to hosts. CONSTITUTION: A first DHCP packet of a host to a port is detected to request assignment of an IP address to a DHCP server. A client hardware address of the host is recorded into a MAC address field of an entry assigned to the host of a database. A second DHCP packet of the port to the host is detected to acknowledge the assignment of the IP address from the DHCP server and the IP address is extracted from the second DHCP packet and is recorded into an IP address field. A transmission packet is detected to extract the hardware address and the IP address of the host. An entry is searched to check the correspondence between the MAC address field and the extracted hardware address and the correspondence between the extracted IP field and the extracted address. The transmission packet is forwarded if the entry is detected. The transmission packet is intercepted if the entry is not detected.