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Controlling Access to File Shares with Forefront TMG 2010
Consider a scenario in which you have an IIS server located in a perimeter network protected by Forefront TMG 2010. The server is published to the Internet and is used to display product information for your company. Web content developers on your internal network need to have access to file shares on the IIS server to upload new web content. To facilitate this access you create an access rule to allow CIFS access to the IIS server. For security reasons you decide to restrict access to members of the Web Content Developers domain group. In addition, your workstations have the Forefront TMG Firewall Client installed. The access rule looks like this:
When users attempt to map a drive to the file share on the web server they receive the following error message:
System error 67 has occurred. The network name cannot be found.
In addition, the Forefront TMG 2010 firewall log indicates the following:
Denied Connection Log Type: Firewall Service Status: The action cannot be performed because the session is not authenticated.
At this point you might be puzzled because you have the Forefront TMG Firewall Client is installed on the workstation. TMG Firewall Client communication is always authenticated, so why does the firewall log indicate otherwise? The answer is simple. The Forefront TMG 2010 Firewall Client is a Layered Service Provider (LSP) that listens for Winsock calls made by the operating system and applications. Any Winsock calls made for resources on a remote network will be transparently delivered to the proxy server by the Firewall Client. However, CIFS communication does not use Winsock, so the TMG Firewall Client does not handle this traffic. As such, the network requests are delivered to the Forefront TMG firewall as SecureNAT requests. Since the rule in question requires authentication, and SecureNAT traffic cannot be authenticated, the firewall appropriately denies the traffic and the request fails.
You can resolve this issue by removing authentication on the access rule and controlling access on the file share itself. If you want to enforce user and group authentication at the firewall, consider using another protocol such as FTP.
For more information about the Forefront TMG 2010 Firewall Client and CIFS connections, please review Microsoft Knowledge Base article 913782.
Error 0x8004FE2F Activating Windows on Forefront TMG 2010 Protected Network
When attempting to activate Windows Server 2008R2 you may receive one of the following error messages:
A problem occurred when Windows tried to activate. Error Code 0x8004FE2F
Or…
A problem occurred when Windows tried to activate. Error Code 0xC004FC03
If you attempt to activate Windows from the command line using slmgr.vbs -ato you may also encounter one of the following error messages:
Activating Window Server(R), ServerEnterprise edition {GUID}...
On a computer running Microsoft Windows non-core edition, run 'slui.exe
0x2a 0x8004FE2F' to display the error text.
Error: 0x8004FE2F
Or…
Activating Window Server(R), ServerEnterprise edition {GUID}...
On a computer running Microsoft Windows non-core edition, run 'slui.exe
0x2a 0x80072EE2' to display the error text.
Error: 0x80072EE2
The problem may occur for systems that are located on a network that is protected by a Forefront TMG 2010 firewall, and the access rule that allows the traffic requires authentication. The Windows activation process relies on WinHTTP and by default, WinHTTP communication is sent as SecureNAT client traffic. SecureNAT clients unfortunately cannot be authenticated, so the request fails.
There are two ways resolve this issue. The first is to configure WinHTTP on the Windows system you are trying to activate to use a proxy serverexplicitly. Open an elevated command prompt and enter the following command:
netsh winhttp set proxy <name or IP address of proxy server>:<port>
For example:
netsh winhttp set proxy tmg.richardhicks.net:8080
Instead of making this change to each system you want to activate, an alternative is to create an anonymous access rule on the Forefront TMG 2010 firewall that allows HTTP and HTTPS traffic to those destinations required to activate Windows. Using the Forefront TMG 2010 management console, create an access rule that allows HTTP and HTTPS from the Internal network to a Domain Name Set that contains the following destinations for all users:
activation.sls.microsoft.com.nsatc.net go.microsoft.com *.sls.microsoft.com
Make sure this rule is placed before any other rules for HTTP or HTTPS that require authentication.
Once configured, activating Windows should work without issue.
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