If you are subscribed to cable broadband internet you may get disconnected if your connection the heartbeat server is interrupted.
In order to fix this problem you must log into your routers web configuration utility by opening up your browser and typing in its relative IP address (e.g. 192.168.0.1) and going to the ‘Status’ screen and pressing the disconnect/connect or renew button. This will re-establish the internet connection.
If you are on an ADSL connection you must have a filter on each phone socket which has a phone attached to it.