A processing unit performs a predetermined process by a remote operation from a client device. A monitoring unit monitors a first port for an unencrypted communication with the processing unit and a second port for an encrypted communication with the processing unit, denies a connection request via the first port, and accepts a connection request via the second port. When a connection request encrypted with either one of the first port and the second port specified as a forwarding destination port is received, an encrypted communication unit decrypts the connection request and transfers decrypted connection request to the monitoring unit via the forwarding destination port.