| 摘要 |
<p>A communicating apparatus that is able to perform IP-FAX communication without making the user aware of the attack and without any difficulty, even if the device recognizes a DoS attack or the like. communication that uses a SIP server on a network is performed by a communicating unit. Unauthorized communication from the communication performed by the communicating unit is detected. A port number of a receiving port of the communicating unit is changed when the unauthorized communication is detected. it is determined whether or not the detected unauthorized communication has passed through the SIP server. The communicating apparatus is controlled to request the SIP server to delete the port number of the receiving port that has not been changed yet if it is determined that the unauthorized communication has passed through the SIP server and to re-register on the SIP server a port number of a receiving port that has been changed if it is determined that the unauthorized communication has bypassed the SIP server.</p> |
