Patent ID: 7895339

Claim:
A network managing method in a communication system, the communication system comprising a first communication node which is attached to a sub-network, a second communication node which is a correspondent node for the first communication node, and a router which is in the sub-network or an upper-level network of the sub-network, the network managing method for verifying if certain information is identification information of the router, comprising: a step where the first communication node acquires the certain information; a step where the first communication node generates a first message including the certain information, and sends the first message to the second communication node; a step where the second communication node generates a second message to reply to the first message and sends the second message to the first communication node, the second message being set so as to be routed to the first communication node via an intermediate router based on the certain information included in the first message, the intermediate router being identified by the certain information; a step where the intermediate router being identified by the certain information intercepts the second message; and a step where the intermediate router being identified by the certain information forwards the second message to the first communication node in a case that the certain information is the identification information of the intermediate router itself, and discards the second message in a case that the certain information is not the identification information of the intermediate router itself.