Patent ID: 7636791

Claim:
An apparatus for detecting an IP (Internet Protocol) address on a network including at least a DNS (Domain Name System) server, comprising: a search IP address detector for detecting at least one search IP address from IP addresses which are a predetermined number of IP addresses selected as a unit from possible IP addresses on the network, by sending an ARP (Address Resolution Protocol) request to the IP addresses and receiving an ARP response to the ARP request; a DNS message transceiver for sending a DNS query message to the at least one search IP address and receiving response message; a DNS server detector for identifying a DNS response message from the response message and detecting an IP address of a source DNS server from the DNS response message; an ICMP message transceiver for sending an ICMP echo request message to the at least one search IP address and receiving ICMP response message; and a router detector for detecting an IP address of a source router from the ICMP response message, wherein the ICMP response message is either an ICMP redirect request message or an ICMP time exceed message.