Patent ID: 6925079
Filing Date: 2005-08-02
Classification: H04L

Abstract:
1. An IP address duplication detection method using an address resolution protocol in a network system in which an IP address duplication diagnosis/detection host and a plurality of check target hosts are connected to a single LAN, all the hosts having MAC addresses as hardware addresses unique to devices without any duplication, there being an address resolution protocol aimed at acquiring a MAC address of a remote device from an IP address installed in each host, comprising the steps of: sending out an ARP request packet containing a check target IP address in the same subnet as for the IP address duplication diagnosis/detection host from the IP address duplication diagnosis/detection host to each of the check target hosts through the LAN; detecting IP address duplication depending on whether an ARP reply packet as a response packet for the ARP request packet is returned from each of the check target hosts to the IP address duplication diagnosis/detection host through the LAN; and maintaining a database listing for each said target IP address, said listing reflecting whether an ARP reply packet was received from no check target hosts, one check target host, or at least two check target hosts.