Kerberos and Network Authentication Issues

Adjust the MaxRequestBytes and MaxFieldLength parameters to increase the accepted header size.

1. Open the Registry Editor on the server where SmartSync Server is installed.
2. Find HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\HTTP\Parameters
3. Create the following DWORD values:
1. aMaxFieldLength
2. MaxRequestBytes
4. Enter a value above 16384 to increase the header size.

To switch to session based Kerberos authentication:

1. Open the command prompt on the server where SmartSync Server is installed.
2. Enter the following commands:
   • cd %SystemRoot%\System32\inetsrv
   • appcmd set config /section:windowsAuthentication /authPersistNonNTLM:true
3. Restart IIS service for your changes to take effect.

Note: The authPersistNonNTLM property controls the re-authorization requirement of Kerberos authentication. Setting this value to true will prevent Kerberos from authenticating every request to SmartSync Server.

To configure NTLM authentication on IIS as fallback:

1. Open the Server Manager.
2. In the right navigation pane click on Roles | Web Server (IIS) | Internet Information Server.
3. In the Connections pane, click on the SmartSync entry.
4. Double-click Authentication.
5. Select Windows Authentication.
6. On the right pane, click Providers. If Provides is not available edit the file applicationHost.config.
7. Promote NTLM above Negotiate:
   1. Select NTLM from the list of Enabled Providers.
   2. Click Move Up until NTLM appears above Negotiate in the list.

1. With Administrator credentials, open C:\Windows\System32\inetsrv\config\applicationHost.config with a text editor.
2. Search for <windowsAuthentication enabled="true" useKernelMode="true" />.

3. Add the following 4 entries between the bold text:

   <windowsAuthentication enabled="true" useKernelMode="true" />
   <providers>
   <add value="NTLM" />
   </providers>
   </windowsAuthentication>
   </authentication>

4. Save and close the file.
5. Restart IIS service for your changes to take effect.