A communications control method is provided for managing a communications system that includes an external network such as the Internet, an internal network and a router. A plurality of clients are connectable to the external network, while a server is connected to the internal network. The external network and the internal network are connected to each other via the router. In accordance with the communication control method, data sent from the client toward the server is stored in a suitable memory. Then, it is determined whether the stored data meets the prescribed delete condition. When this condition is met, the data is deleted from the memory.