Patent ID: 7639690

Claim:
A network communication monitoring system, in which a central apparatus and a plurality of terminal devices are connected via a relay unit so as to permit data communication via a plurality of networks; and the central apparatus monitors continuation and blockade of the network connection with respect to the plural terminal devices by transmission and reception of a request packet and a reply packet due to a communication monitoring command, wherein the central apparatus comprises: means for obtaining destination information of the plural terminal devices; means for generating one request packet with obtained plural destination information consolidated; and means for transmitting one generated request packet, the relay unit comprises: means for receiving the one request packet; means for generating a plurality of request packets on the basis of the consolidated destination information; means for transmitting the generated request packet; means for receiving reply packets from the terminal devices; means for generating one reply packet by consolidating the destination information of transmission origins of the received reply packets; and means for returning one generated reply packet to the central apparatus, and the central apparatus further comprises: means for receiving one returned reply packet; and means for determining continuation and blockade of the network connection for each terminal device on the basis of the destination information of the consolidated transmission origin.