Inbound Connections Limit in Windows NT Workstation 3.5x & 4.0

• Microsoft Windows NT Workstation versions 3.5, 3.51, and 4.0

SYMPTOMS

When a user at a computer running Windows NT attempts to connect to a Windows NT Workstation system that already has ten users connected to it, the following error message appears:

   No more connections can be made to this remote computer at this time
   because there are already as many connections as the computer can
   accept.

   Error 71. The network request was not accepted.

CAUSE

Ten is the maximum number of other computers that are permitted to simultaneously connect over the network to Windows NT Workstation 3.5, 3.51, and 4.0. This limit includes all transports and resource sharing protocols combined.

This limit is the number of simultaneous sessions from other computers the system is permitted to host. This limit does not apply to the use of administrative tools that attach to the system from a remote computer.

NOTE: This limitation only applies to inbound connections to Windows NT Workstation 3.5, 3.51, and 4.0. When you use Windows NT Workstation 3.5, 3.51, and 4.0, unlimited connections (outbound connections) can be established to other systems.

WORKAROUND

Any file, print, named pipe, or mail slot session that does not have any activity on it will be automatically disconnected after the AutoDisconnect time has expired; the default for this is 15 minutes. Once the session is disconnected, one of the 10 connections will be available so that another user can connect to the Windows NT Workstation system. Therefore, lowering the AutoDisconnect time can help to reduce some of the problems users may encounter with the 10-connection limit on a system that is not used heavily for server purposes.

You can configure the AutoDisconnect time by running the following command from a command prompt:

   net config server /autodisconnect:<time_before_autodisconnect>

NOTE: The Windows NT Server service is self-tuning, normally the server configuration parameters are auto-configured (calculated and set) each time you boot Windows NT. If you run NET CONFIG SERVER in conjunction with the /AUTODISCONNECT, /SERVCOMMENT or /HIDDEN switches, the current values for the automatically tuned parameters are displayed and written to the registry. Once these parameters are written to the registry, you cannot tune the Server service using Control Panel Networks. If you changed any of the Server service settings, Windows NT is no longer able to automatically tune the Server service for your new configuration. To avoid losing the Server service's auto self-tuning capability, make the change through registry editor instead from a command line or Control Panel Network.

For more information, see the following articles in the Microsoft Knowledge base:

   ARTICLE-ID: Q128167
   TITLE     : Server Service Configuration and Tuning

   ARTICLE-ID: Q138365
   TITLE     : How the Autodisconnect Works in Windows NT

MORE INFORMATION

All logical drive, logical printer, and transport level connections combined from a single computer are considered to be one session; therefore, these connections only count as one connection in the 10- connection limit. For example, if a user establishes two logical drive connections, two Windows sockets, and one logical printer connection to a Windows NT Workstation system, one session is established. As a result, there will be only one less connection that can be made to the Windows NT Workstation system, even though three logical connections have been established.

The only way system A will have multiple sessions to another system, system Z, is if system A is running services that create logical connections to system Z. For example, if a user is logged on to system A as guest and a service is running on system A under the user1 account, and both the user and the service (as user1) establish connections to system Z, two sessions will be established. Each logon session that uses the Server service counts against the connection limit.