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Q127789: LAN Manager Clients Cannot See Windows NT Computers

Article: Q127789
Product(s): Microsoft Windows NT
Version(s): 3.5 4.0
Operating System(s): 
Keyword(s): kbnetwork
Last Modified: 08-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Workstation versions 3.5, 3.51, 4.0 
- Microsoft Windows NT Server versions 3.5, 3.51, 4.0 
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SYMPTOMS
========

When you run NET VIEW on a LAN Manager client, the list of Windows NT
workstations and servers in the domain is not available for several minutes.

CAUSE
=====

This problem occurs due to the Windows NT broadcast design.

NOTE: To make Windows NT workstations and servers visible to LAN Manager clients,
you must configure the Windows NT computers to broadcast server announcements to
LAN Manager clients. To do this, run Control Panel, choose Network, select
Server, choose Configure, the select "Make Browser Broadcast to LAN Manager 2.x
clients," and choose OK.

On Windows NT 4.0 machines, use REGEDT32.EXE to set the * entry in
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanManServer\Parameter s\
to 1.

STATUS
======

Microsoft has confirmed this to be a problem in Windows NT version 3.5. This
problem has been corrected in the latest U.S. Service Pack for Windows NT
version 3.5. For information on obtaining the Service Pack, query on the
following word in the Microsoft Knowledge Base (without the spaces):

  S E R V P A C K

MORE INFORMATION
================

Original Design
---------------

LAN Manager clients rely on server announcements that are broadcast over second
class mailslots. The LAN Manager clients pickup server announcements and store
them (for 1.5 times the announcement rate). If you run NET VIEW and the stored
server announcement is still valid, the server name and server comments are
displayed. If the next server announcement is not received by the client within
1.5 times the announcement rate, the server is dropped from the list. So if a
client receives a server announcement at one minute intervals, it is likely to
drop the server from the list if it does not receive another announcement in 1.5
minutes.

Here is a sample server announcement from USER1STA to LAN Manager clients:

  USER1STA *NETBIOS Multicast SMB C transact, File = \MAILSLOT\LANMAN
  NETBIOS: Datagram (0x08), USER1STA         -> USER1DOM       <00>

        -----

  NETBIOS: Destination Name = USER1DOM       <00>

      NETBIOS: SMB Name Type = Workstation (00)
      NETBIOS: Source Name = USER1STA
      NETBIOS: SMB Name Type = Server (20)
      NETBIOS: NetBIOS Data: Number of data bytes remaining = 115

  SMB: C transact, File = \MAILSLOT\LANMAN

     ------

  SMB: Command = C transact

     ------

  SMB: Mailslot class = Unreliable (broadcast)

          SMB: Byte count = 46
          SMB: Byte parameters
          SMB: Path name  = \MAILSLOT\LANMAN
          SMB: Transaction data
          SMB: Server announce opcode = Server announcement
          SMB: Service Flags Summary = 4097 (0x1001)
           SMB: .....................1 = Workstation service running
           SMB: ......................0. = Server service not available
          SMB: Major version = 3
          SMB: Minor version = 50
          SMB: Server announce rate = 720
          SMB: Computer name = USER1STA
          SMB: Server comment = User1's System;

NOTE: USER1STA sends a Multicast datagram to destination NetBIOS group name
USER1DOM<00>. All LAN Manager clients post a NetBIOS Receive on their own
domain, as well as other domains listed in their LANMAN.INI file, during
initialization.

The server announce rate is set is seconds. Therefore, the server announce rate
of 720 in the above example, it equates to 12 minutes. In Windows NT 3.1, the
announce LAN Manager Server parameter in the registry could be used to set the
announcement interval. However, in Windows NT workstation and Windows NT Server
version 3.5, a new algorithm was developed. The server announcements are made
during the start of the server service, and at the following approximate
intervals:

  .5, 1, 1.5, 4, 8, 12, remain at 12 minutes].

For example:

  #  Time     Src         Description
  1  27.390   USER1STA    C transact, File = \MAILSLOT\LANMAN (30sec)
  2  50.303   USER1STA    C transact, File = \MAILSLOT\LANMAN (~20).
  3  79.151   USER1STA    C transact, File = \MAILSLOT\LANMAN (~30)
  4  348.700  USER1STA    C transact, File = \MAILSLOT\LANMAN (~260)
  5  861.290  USER1STA    C transact, File = \MAILSLOT\LANMAN (~520)
  6  1586.99  USER1STA    C transact, File = \MAILSLOT\LANMAN (~720)
  7  2312.10  USER1STA    C transact, File = \MAILSLOT\LANMAN (~720)
  8  3033.39  USER1STA    C transact, File = \MAILSLOT\LANMAN (~720)
  9  3758.56  USER1STA    C transact, File = \MAILSLOT\LANMAN (~720)

The announce parameter is ignored.

As a result, you may not see Windows NT workstation and server names when you run
NET VIEW on LAN Manager clients, right after you boot the computer. The longest
wait time, if you just miss a server announcement, would be 12 minutes. Once you
receive the server announcement, it is valid for 18 minutes.

New Design
----------

The default initial announce frequency for LAN Manager clients is now four
minutes, and increases to once every 12 minutes.

The AnnDelta delta parameter, although adjustable, defaults to 3000 milliseconds.
This parameter specifies the time by which the announcement period can vary.
This helps to prevent several servers from continuously announcing
simultaneously, thereby reducing network load peaks.

Additional query words: prodnt browsing mail slots server message block

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Keywords          : kbnetwork 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT351search kbWinNT350search kbWinNT400search kbWinNTW350 kbWinNTW350search kbWinNTW351search kbWinNTW351 kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbWinNTS351 kbWinNTS350 kbWinNTS351search kbWinNTS350search
Version           : 3.5 4.0

=============================================================================

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