Microsoft KB Archive/275020

= SMB Signing May Become Unsynchronized =

Article ID: 275020

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Workstation 4.0
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 4.0 Standard Edition
 * Microsoft Windows NT 4.0 Service Pack 4
 * Microsoft Windows NT 4.0 Service Pack 5
 * Microsoft Windows NT 4.0 Service Pack 6
 * Microsoft Windows NT 4.0 Service Pack 6a

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This article was previously published under Q275020



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 &quot;ACCESS_DENIED.&quot;



RESOLUTION
A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are 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 about support costs, visit the following Microsoft Web site:

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

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual 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:

299444 Post-Windows NT 4.0 Service Pack 6a Security Rollup Package (SRP)



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

Keywords: kbbug kbfix kbqfe kbhotfixserver KB275020

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