Abstract: A communications device has a first communications port via which secure messages are received, and a second communications port via which non-secure messages are received. In response to detecting that a secure message has been received, the device determines whether the second communications port is in a state that enables non-secure messages to be received. If the second communications port is in the enabled state, the device autonomously disables the second communications port to preclude non-secure messages received at that port from being processed.