"Access Denied" Accessing Windows 95 Share from Windows NT 4.0

ID: Q169841

This article discusses a Beta release of a Microsoft product. The information in this article is provided as-is and is subject to change without notice.

No formal product support is available from Microsoft for this Beta product. For information about obtaining support for a Beta release, please see the documentation included with the Beta product files, or check the Web location from which you downloaded the release.

The information in this article applies to:

Microsoft Windows 95
Microsoft Windows 95 OEM Service Release version 1
Microsoft Windows NT Workstation version 4.0
Microsoft Windows NT Server version 4.0
Microsoft Windows 95 OEM Service Release version 2
Microsoft Windows 95 OEM Service Release version 2.1
Microsoft Windows 2000 Professional
Microsoft Windows 2000 Server

SYMPTOMS

When you attempt to connect to a share on a Windows 95-based computer from a Windows NT 4.0 workstation or server or Windows 2000, the connection attempt may not succeed and you may receive an "Access Denied" error message if the following conditions exist:

The Windows 95 server has user-level security enabled (instead of share-level security), and the security provider is a Windows NT domain.

You are attempting to connect to the Windows 95-based computer by using a UNC name (\\servername\sharename) instead of by mapping a drive letter to the share.

The Windows NT 4.0 workstation or server has Service Pack 2 or Service Pack 3 installed.

This behavior can also occur with Windows 98-based computers connecting to Windows 95-based computers, and from Windows 95-based computers with the DFS client installed talking to Windows 95-based computers.

CAUSE

This symptom is the result of an interoperability problem between Windows NT 4.0 with Service Pack 2 or Service Pack 3 installed and Windows 95. Windows NT 4.0 with Service Pack 2 or Service Pack 3 makes a connection using a null user name, which Windows 95 does not handle correctly.

RESOLUTION

This issue is resolved by the following updated file for Windows 95 and OSR1, and later versions of this file:


    VSERVER.VXD  version 4.00.954  dated 4/24/97  108,288 bytes

This issue is resolved by the following updated file for Windows 95 OSR2 and OSR 2.x, and later versions of this file:


    VSERVER.VXD  version 4.00.1112  dated 7/24/97  112,904 bytes

STATUS

Microsoft has confirmed this to be a problem in Microsoft Windows 95 and OEM Service Release 2 (OSR2). An update to address this problem is now available, but is not fully regression tested and should be applied only to computers experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft does not recommend implementing this update at this time. Contact Microsoft Technical Support for additional information about the availability of this update.

This issue is resolved in Microsoft Windows 98.

MORE INFORMATION

Windows NT 4.0 Service Pack 2 (SP2) uses a new version of the Multiple UNC Provider (MUP) that contains new code for DFS. This code establishes a null session when you connect to a server. The Windows 95 File And Print Sharing service for Microsoft Networks (Vserver) does not handle the null session correctly and tries to use a null user name to check for the access rights. When the MUP null session requests arrives at Vserver, SessSetupX calls AccessLogon.

Because smb_uid is always zero, even for TESTUSER, there is no way to distinguish user TESTUSER from the null-session user. Vserver uses the null user name for credentials checking in further SMB commands and you receive the

Access Denied

error message.

For additional information about issues resolved by updates to this component, please see the following articles in the Microsoft Knowledge Base:

Q137980 Connecting to Windows 95 User Level Share Results Event ID 3012

Q128079 Updated Drivers for File and Printer Sharing Security

For additional information about Windows 95 updates, please see the following article in the Microsoft Knowledge Base:

Q161020 Implementing Windows 95 Updates

Additional query words: win95 win95x winnt browse browsing

Keywords : kberrmsg kbnetwork osr2 NTSrvWkst
Version : WINDOWS:2000,95; winnt:4.0
Platform : WINDOWS winnt
Issue type : kbprb