Microsoft KB Archive/163877

= Problems Copying Files To Novell NetWare 3.11 =

Article ID: 163877

Article Last Modified on 11/1/2006

-

APPLIES TO


 * Microsoft Windows NT Workstation 3.51
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 3.51
 * Microsoft Windows NT Server 4.0 Standard Edition

-



This article was previously published under Q163877



SYMPTOMS
You may experience problems copying files on a Token Ring network from a computer running Windows NT to a Novell server running NetWare 3.11 (or earlier).

Attempts to copy files (using File Manager, for example) over a certain size may fail with the following error :

The Remote Computer is Not Available



CAUSE
Windows NT's Nwrdr.sys calculates an incorrect maximum packet size under these specific circumstances.



RESOLUTION
WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.

To work around this problem, perform the following steps:
 * 1) Start Registry Editor (Regedt32.exe) and go to the following subkey:

NOTE: The above registry key is one path; it has been wrapped for readability.
 * 1) Select the DefaultMaxPacketSize parameter and set number to a MaxPktSize number minus 85.

For example, if you have specified a MaxPktSize of 1500, you should set DefaultMaxPacketSize to 1415. That is, 1500 minus 85 = 1415.



STATUS
Microsoft has confirmed this to be a problem in Windows NT version 3.51 And Windows NT version 4.0. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.



MORE INFORMATION
For this problem to occur, the following conditions must apply:
 * 1) PBURST is enabled on the computer running Windows NT.
 * 2) The NetWare server refuses the computer running Windows NT PBURST request.
 * 3) You have specified a value for the following registry parameter:

NOTE: The above registry key is one path; it has been wrapped for readability.

that is smaller than the buffer size the computers would normally negotiate by default if this value was absent from the registry.

MaxPktSize (a REG_DWORD) is usually used to limit the size of transmitted frames, to permit communications through routers whose largest maximum transfer unit (MTU) is smaller than that of the Token Ring medium in use.

If MaxPktSize is specified, problems may be encountered when attempting to transfer files larger in size than MaxPktSize number minus 85.

Note that for the NetWare server to refuse a PBURST request it must be running a version of NetWare earlier than 3.11 (for which PBURST is not available) or it must be running NetWare 3.11 and not have PBURST.NLM loaded. In NetWare 3.12 and later, PBURST support is built into the operating system and it cannot be disabled. If the NetWare server is running 3.11 with PBURST.NLM loaded, or is running 3.12 or later, you should not see this problem.

The Magic Number of 85 is an allowance for the following:

  Token Ring Header................ 14 bytes Token Ring Source Routing Info... 18 bytes max LLC Header....................... 3 bytes NCP Packet Header................ 30 bytes NCP Write Request................ 7 bytes File Write Request............... 13 bytes

Total............................ 85 bytes max

Additional query words: CSNW GSNW

Keywords: kbbug kbnetwork KB163877

-

[mailto:TECHNET@MICROSOFT.COM Send feedback to Microsoft]

© Microsoft Corporation. All rights reserved.