Patent ID: 8725897

Claim:
A communication apparatus capable of communicating with an external device through a communication line, the communication apparatus comprising: a register unit configured to register, in a storage unit, a first IP address of an external device which is refused to communicate with the communication apparatus, wherein the first IP address is an address of a plurality of IP addresses assigned to the external device; an obtaining unit configured to obtain, when the first IP address is registered by the register unit, a second IP address of the external device indicated by the registered first IP address, wherein the second IP address is an address of the plurality of IP addresses assigned to the external device; an additional register unit configured to register, in the storage unit, the second IP address obtained by the obtaining unit as an IP address which is refused to communicate with the communication apparatus; a determination unit configured to, when receiving information from an external device, determine whether or not a sender IP address included in the information is registered in the storage unit; and a filtering controller configured to refuse reception of the information from the external device in a case that the determination unit determines that the sender IP address is registered in the storage unit.