Network connections are cut

Windows 2000 Server cuts my client network connections after a period of time if the connection is not used. This affects certain software that is being used at the time that relies on the network link when finally closing a file on the server, i.e. Autodesk Inventor 5 creates a project file on the server whenever a new file is created and does not automatically save all components using autosave. Can anybody resolve the premature termination of the connection.