When you configure a Windows Server 2008-based or a Windows Vista-based computer to use a public network, the eventing port of network discovery is closed. This port is used by some Windows Services on Devices printers to send status information. Because this port is blocked, the client does not receive JobEndStateEvent notifications, such as Print Job cancelation notifications. In this scenario, multiple print jobs may be pending in the print queue. Or, a print job may not be canceled, and the print queue is not released for more printing.