We have an MS SBS 4.5 server running Proxy Server 2 connected to Demon via an USRobotics ISDN modem attached to the server's serial port. Exchange v5.5 also using this connection with scheduled times to call to retrieve mail..
We are experiencing times when the line stays up for hours at a time even when all PCs on the network are switched off. Time out is set to 2 minutes inactivity.
NetBeui is not running as a protocol - only TCP/IP and IPX. There is a Novell server on the network as well.
Latest USR drivers are installed.
We had no problem with exactly the same set up using an Analogue phone.
Any ideas on what is causing the line to stay active ?