DOCUMENT:Q275020  08-MAY-2002  [winnt]
TITLE   :SMB Signing May Become Unsynchronized
PRODUCT :Microsoft Windows NT
PROD/VER::4.0,4.0 SP4,4.0 SP5,4.0 SP6,4.0 SP6a
OPER/SYS:
KEYWORDS:kbWinNT400PreSP7Fix

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The information in this article applies to:

 - Microsoft Windows NT Workstation versions 4.0, 4.0 SP4, 4.0 SP5, 4.0 SP6, 4.0 SP6a 
 - Microsoft Windows NT Server versions 4.0, 4.0 SP4, 4.0 SP5, 4.0 SP6, 4.0 SP6a 
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SYMPTOMS
========

When a session is established from a workstation to a server, and server message
block (SMB) signing is enabled, the signatures may become out of synchronization
and cause all subsequent requests that are sent by the workstation to be
rejected by the server. This is more likely to occur if the workstation and
server are separated by a slow WAN link.

CAUSE
=====

This behavior occurs only if there is an active SMB session established to the
same server to which the workstation is trying to connect. If the workstation
sends an SMB from the other session while the SMB session setup for the new
session is outstanding, the signature count on the server may become out of
synchronization with the signature count on the workstation. This results in all
subsequent SMB commands that are sent to the server being rejected. All
responses after this point are returned to the workstation with a status of
"ACCESS_DENIED."

RESOLUTION
==========

A supported fix is now available from Microsoft, but it is only intended to
correct the problem described in this article and should be applied only to
systems experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the
fix. For a complete list of Microsoft Product Support Services phone numbers and
information on support costs, please go to the following address on the World
Wide Web:

   http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

NOTE: In special cases, charges that are normally incurred for support calls may
be canceled, if a Microsoft Support Professional determines that a specific
update will resolve your problem. Normal support costs will apply to additional
support questions and issues that do not qualify for the specific update in
question.

The English version of this fix should have the following file attributes or
later:

 Date        Time     Version       Size     File name  Platform
 ------------------------------------------------------------------
 03/01/2001  11:12pm  4.0.1381.7086  266,224  Rdr.sys    Intel



To resolve this problem, obtain the individual package referenced earlier, or
obtain the Windows NT 4.0 Security Rollup Package. For additional information
about the Security Rollup Package, click the article number below to view the
article in the Microsoft Knowledge Base:

   Q299444 Post-Windows NT 4.0 Service Pack 6a Security Rollup Package (SRP)


STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products that are
listed at the beginning of this article.

Additional query words:

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Keywords          : kbWinNT400PreSP7Fix 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTW400sp5 kbWinNTW400sp4 kbWinNTSsearch kbWinNTS400sp6 kbWinNTS400sp5 kbWinNTS400sp4 kbWinNTS400search kbWinNTS400 kbWinNTW400sp6 kbWinNTW400SP6a
Version           : :4.0,4.0 SP4,4.0 SP5,4.0 SP6,4.0 SP6a
Hardware          : ALPHA x86
Issue type        : kbbug
Solution Type     : kbfix

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