Patent ID: 8023512

Claim:
A communication device comprising: a receiving unit that receives a packet transmitted from outside via a network; a setting storage unit that stores discard address definition information as information to represent a source address of a packet to be discarded; an interface which allows a user to update the discard address definition information; a web server which provides the interface with a web page including a setting screen for accepting update operation of the discard address definition information; a discard determination unit that determines whether a packet received by the receiving unit should be discarded based on the discard address definition information stored in the setting storage unit; a transmission control unit that discards a packet determined to be discarded by the discard determination unit and transmits downstream a packet determined not to be discarded by the discard determination unit; a report unit that reports information on discarding of a packet to a predetermined report destination in case the packet is to be discarded by the transmission control unit, wherein the information on discarding of the packet includes link information to the setting screen; a report history storage unit that stores the source address of the packet as a cause of report in case the report unit reports the information; and a report necessity determination unit that determines whether information on discarding of a packet needs to be reported in response to discarding of the packet by the transmission control unit based on a storage content of the report history storage unit, wherein the report unit reports information on discarding of a packet to the predetermined report destination only concerning discarding of a packet determined necessary to be reported in accordance with the determination result of the report necessity determination unit, wherein the communication device comprises an attribute information acquisition unit that acquires attribute information corresponding to the source address of a packet discarded by the transmission control unit from a database server included in the network for storing the attribute information of each terminal device in the network in association with a node address assigned to each terminal device, and the report unit reports information including the attribute information on the corresponding packet acquired by the attribute information acquisition unit as information on discarding of the packet, and wherein the attribute information includes information of a group to which the terminal device belongs, where the group information is different from IP address.