One embodiment of the present method and apparatus for time-based communications port protection includes generating a transmission period schedule that is known only by authorized network users including a server and one or more clients of the server. The transmission period schedule dictates pre-defined times at which the server and clients may communicate, e.g., to transfer data. By communicating only at these secret, pre-defined times, the likelihood that an unauthorized party will be able to disrupt service to the clients is greatly reduced.