A method for informing a connection condition between an external device and a router, includes: monitoring whether a predetermined event occurs, the predetermined event being one of connecting the external device to the router or disconnecting the external device from the router; determining a registered port of a plugin of the router from one or more ports of a plugin center, if the predetermined event occurs; and sending to the plugin, through the registered port of the plugin, a first notification to indicate that the predetermined event occurs.