Article ID: 839499
Article Last Modified on 12/3/2007
APPLIES TO
- Microsoft Windows Small Business Server 2003 Premium Edition
- Microsoft Windows Small Business Server 2003 Standard Edition
- Microsoft Windows Server 2003, 64-Bit Datacenter Edition
- Microsoft Windows Server 2003, Enterprise x64 Edition
- Microsoft Windows Server 2003, Datacenter Edition (32-bit x86)
- Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
- Microsoft Windows Server 2003, Standard Edition (32-bit x86)
- Microsoft Windows 2000 Datacenter Server
- Microsoft Windows 2000 Advanced Server
- Microsoft Windows 2000 Server
Important This article contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:
256986 Description of the Microsoft Windows registry
SUMMARY
This article discusses how to resolve the following two problem scenarios that may occur in Microsoft Windows Server 2003 or in Microsoft Windows 2000 Server:
- Server message block (SMB) signing is disabled for the Workstation service on a domain controller, but SMB signing is required for the Server service on the same domain controller.
- SMB signing is disabled for the Server service on a domain controller, but SMB signing is required for the Workstation service on the same domain controller.
SYMPTOMS
Scenario 1 - SMB signing is disabled for the Workstation service on a domain controller, but SMB signing is required for the Server service on the same domain controller.
Windows Server 2003
When you try to open Group Policy snap-ins on the domain controller, you receive an error message that is similar to the following:
The server logs the following events in the application event log every five minutes:
When you log on to the server locally and then try to open shares on the server, you receive repeated password prompts, and you cannot open the shares.
Windows 2000 Server
When you try to open Group Policy snap-ins on the domain controller, you receive an error message that is similar to the following:
The domain controller logs the following event in the application event log:
When you log on to the server locally and then try to open shares on the server, you receive repeated password prompts, and you cannot open the shares.
Scenario 2 - SMB signing is disabled for the Server service on a domain controller, but SMB signing is required for the Workstation service on the same domain controller.
Windows Server 2003
When you try to open Group Policy snap-ins on the domain controller, you receive an error message that is similar to the following:
In a network trace, if SMB signing is enabled and required at the client and is disabled at the server, the connection to the TCP session is gracefully closed after the Dialect Negotiation, and the client receives the following error:
The domain controller logs the following events in the application event log every five minutes:
When you log on to the server locally and then try to open file shares on the server, you receive an error message that is similar to the following:
Note In a network trace, if SMB signing is enabled, and if SMB signing is required at the client and is disabled at the server, the connection to the TCP session is gracefully closed after the dialect negotiation. Also, the client receives the following error message:
Windows 2000 Server
When you try to open Group Policy snap-ins on the domain controller, you receive an error message that is similar to the following:
The domain controller logs the following event in the application event log every five minutes:
When you log on to the server locally and then try to open file shares on the server, you receive an error message that is similar to the following:
Note In a network trace, if SMB signing is enabled, and if SMB signing is required at the client and is disabled at the server, the connection to the TCP session is gracefully closed after the dialect negotiation. Also, the client receives the following error message:
CAUSE
This behavior occurs if the SMB signing settings for the Workstation service and for the Server service contradict each other. When you configure the domain controller in this way, the Workstation service on the domain controller cannot connect to the domain controller's Sysvol share. Therefore, you cannot start Group Policy snap-ins. Also, if SMB signing policies are set by the default domain controller security policy, the problem affects all the domain controllers on the network. Therefore, Group Policy replication in the Active Directory directory service will fail, and you will not be able to edit Group Policy to undo these settings.
RESOLUTION
To resolve this behavior, follow these steps.
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
- On the domain controller, click Start, click Run, type regedit, and then click OK.
- Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters
- In the right pane, double-click enablesecuritysignature, type 1 in the Value data box, and then click OK.
- Double-click requiresecuritysignature, type 1 in the Value data box, and then click OK.
- Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanworkstation\parameters
- In the right pane, double-click enablesecuritysignature, type 1 in the Value data box, and then click OK.
- Double-click requiresecuritysignature, type 0 in the Value data box, and then click OK.
- After you change these registry values, restart the Server and Workstation services. Do not restart the domain controller, because this action may cause Group Policy to change the registry values back to the earlier values.
- Open the domain controller’s Sysvol share. To do this, click Start, click Run, type \\
Server_Name\Sysvol, and then press ENTER. If the Sysvol share does not open, repeat steps 1 through 8. - Repeat steps 1 through 9 on each affected domain controller to make sure that each domain controller can access its own Sysvol share.
- After you connect to the Sysvol share on each domain controller, open the Domain Controller Security Policy snap-in, and then configure the SMB signing policy settings. To do this, follow these steps:
- Click Start, point to Programs, point to Administrative Tools, and then click Domain Controller Security Policy.
- In the left pane, expand Local Policies, and then click Security Options.
- In the right pane, double-click Microsoft network server: Digitally sign communications (always).
Note In Windows 2000 Server, the equivalent policy setting is Digitally sign server communication (always).
Important If you have client computers on the network that do not support SMB signing, you must not enable the Microsoft network server: Digitally sign communications (always) policy setting. If you enable this setting, you require SMB signing for all client communication, and client computers that do not support SMB signing will not be able to connect to other computers. For example, clients that are running Apple Macintosh OS X or Microsoft Windows 95 do not support SMB signing. If your network includes clients that do not support SMB signing, set this policy to disabled.
- Click to select the Define this policy setting check box, click Enabled, and then click OK.
- Double-click Microsoft network server: Digitally sign communications (if client agrees).
Note For Windows 2000 Server, the equivalent policy setting is Digitally sign server communication (when possible). - Click to select the Define this policy setting check box, and then click Enabled.
- Click OK.
- Double-click Microsoft network client: Digitally sign communications (always).
- Click to clear the Define this policy setting check box, and then click OK.
- Double-click Microsoft network client: Digitally sign communications (if server agrees).
- Click to clear the Define this policy setting check box, and then click OK.
- Run the Group Policy Update utility (Gpupdate.exe) with the force switch. To do this, follow these steps:
- Click Start, click Run, type cmd, and then click OK.
- At the command prompt, type gpupdate /force, and then press ENTER.
For more information about the Group Policy Update utility, click the following article number to view the article in the Microsoft Knowledge Base:
298444 A description of the Group Policy Update utility
Note The Group Policy Update utility does not exist in Windows 2000 Server. In Windows 2000, the equivalent command is secedit /refreshpolicy machine_policy /enforce.
For more information about using the Secedit command in Windows 2000, click the following article number to view the article in the Microsoft Knowledge Base:227302 Using SECEDIT to force a Group Policy refresh immediately
- After you run the Group Policy Update utility, check the application event log to make sure that the Group Policy settings were updated successfully. After a successful Group Policy update, the domain controller logs Event ID 1704. This event appears in the Application Log in Event Viewer. The source of the event is SceCli.
- Check the registry values that you changed in steps 1 through 7 to make sure that the registry values have not changed.
Note This step makes sure that a conflicting policy setting is not applied at another group or organizational unit (OU) level. For example, if the Microsoft network client: Digitally sign communications (if server agrees) policy is configured as "Not Defined" in Domain Controller Security Policy, but this same policy is configured as disabled in Domain Security Policy, SMB signing will be disabled for the Workstation service. - If the registry values have changed after you run the Group Policy Update utility, open the Resultant Set of Policy (RSoP) snap-in in Windows Server 2003. To start the RSoP snap-in, click Start, click Run, type rsop.msc in the Open box, and then click OK.
In the RSoP snap-in, the SMB signing settings are located in the following path:Computer Configuration/Windows Settings/Security Settings/Local Policies/Security Options
Note If you are running Windows 2000 Server, install the Group Policy Update utility from the Windows 2000 Resource Kit, and then type the following at the commmand prompt:
After you run this command, the Applied Group Policy Objects list appears. This list shows all Group Policy objects that are applied to the computer account. Check the SMB signing policy settings for all these Group Policy objects.gpresult /scope computer /v
MORE INFORMATION
If you run the domain controller diagnostic tool (DcDiag.exe) in scenario 1, you receive errors that are similar to the following for Windows 2000 and for Windows Server 2003:
If you run the domain controller diagnostic tool in scenario 2, you receive errors that are similar to the following for Windows 2000 and for Windows Server 2003:
The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.
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