Delay in NetBIOS Connections from a Multihomed Computer (187735)

SYMPTOMS

When a NetBIOS connection is established from a multihomed computer running TCP/IP protocol to another computer, it might experience a delay in completing the connection.

On versions of Windows NT earlier than Windows NT 4.0 Service Pack 3 (SP3), a multihomed computer will always try to establish a NetBIOS session using the primary transport bound to the redirector before it tries other transports.

For additional information about this feature, please see the following article:

ARTICLE-ID: 166159
TITLE : NetBIOS Connections from a Multihomed Computer

CAUSE

When the redirector accepts the first transport that responds to complete the call, it will issue cancel calls to the primary transport and all other transports if applicable. It will then wait until all cancels are returned before it continues with the session setup process on the accepted transport. NetBT does not respond to a cancel call immediately until its session setup is complete or times out (that is, going through all its name resolution methods). This will cause a redirector delay in the session setup on the accepted transport.

RESOLUTION

To resolve this problem, contact Microsoft Technical Support to obtain the following fix, or wait for the next Windows NT service pack.

This fix should have the following time stamp:

12/18/97	08:43p	119,856	Netbt.sys	(Intel)
12/18/97	08:40p	220,048	Netbt.sys	(Alpha)

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0.

A supported fix is now available, but has not been fully regression tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next service pack that contains this fix. Contact Microsoft Technical Support for more information.

MORE INFORMATION

This problem and hotfix do not apply to Windows Sockets-based connections. When a Windows Sockets application places a call from a multi-homed host the best local source address is chosen automatically (using the route table), unless the application specifies otherwise by choosing a local IP address to use in the bind() call.

This behavior was changed in Windows NT Service Pack 3, where you can set a registry parameter that causes the redirector to accept the first transport to complete a call, rather than waiting for success or failure on the primary transport.