Windows can automatically hang up a dial-up Internet connection when it is no longer needed. This is particularly useful if the line is shared with a phone or you are on an hourly rate.

If Internet Explorer doesn't disconnect automatically, run Tools/Internet Options. Click on the Connections tab, then select the dial-up connection in the list and click Settings. Click the Advanced button in the next dialogue box and tick Disconnect when connection is no longer needed. If on a timed connection, tick Disconnect if idle for xxx minutes so that you don't inadvertently run up a large bill.

If you have broadband, or a separate phone line together with unlimited hours, you may prefer to not have the connection hang up. In this case, not only untick Disconnect when connection is no longer needed, but also untick Disconnect if idle for xxx minutes.