Cannot establish an L2TP VPN connection between an Android device and a TMG server

Applies to: Windows Server 2008 R2 StandardWindows Server 2008 R2 EnterpriseWindows Server 2008 R2 Datacenter


Consider the following scenario:
  • You install Microsoft Forefront Threat Management Gateway (TMG) 2010 on a computer that is running Windows Server 2008 R2.
  • You configure a TMG server as a Routing and Remote Access service (RRAS) server. Additionally, you configure the server to use Layer 2 Tunneling Protocol (L2TP) connections.
  • You establish an L2TP VPN connection between the TMG server and an Android device.
In this scenario, the connection is disconnected after about 10 seconds.


This issue occurs because the Android device restarts Compression Control Protocol (CCP) negotiation after the Point-to-Point Protocol (PPP) connection is established. This behavior triggers the RRAS server to treat the Android device as a Network Access Protection (NAP) capable device and to try to authenticate the device. The TMG server then denies the request to authenticate the device, and the issue that is described in this Microsoft Knowledge Base (KB) article occurs.


Hotfix information

Important This hotfix has been re-released to address an issue in which the digital signature on files produced and signed by Microsoft will expire prematurely, as described in Microsoft Security Advisory 2749655.

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.


To apply this hotfix, you must be running Windows Server 2008 R2 Service Pack 1 (SP1).For more information about how to obtain a Windows Server 2008 R2 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

976932 Information about Service Pack 1 for Windows 7 and for Windows Server 2008 R2

Registry information

To use the hotfix, you do not have to change the registry.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.
Windows Server 2008 R2 file information notes
Important Windows 7 hotfixes and Windows Server 2008 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 7/Windows Server 2008 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.
  • The files that apply to a specific product, milestone (RTM,SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
    VersionProductMilestoneService branch
    Windows Server 2008 R2SP1LDR
  • The MANIFEST files (.manifest) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 R2" section. MANIFEST files and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.
For all supported x64-based versions of Windows Server 2008 R2
File nameFile versionFile sizeDateTimePlatform


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

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.

Additional file information

Additional file information for Windows Server 2008 R2

Additional files for all supported x64-based versions of Windows Server 2008 R2
File nameAmd64_4301f34cb8dd9a3502f19af3a7ce359a_31bf3856ad364e35_6.1.7601.22044_none_0bb0f321e96630d2.manifest
File versionNot Applicable
File size1,042
Date (UTC)17-Sep-2012
Time (UTC)14:40
PlatformNot Applicable
File nameAmd64_microsoft-windows-rasmprddm_31bf3856ad364e35_6.1.7601.22044_none_f7a5616efd6df42b.manifest
File versionNot Applicable
File size13,632
Date (UTC)04-Jul-2012
Time (UTC)22:42
PlatformNot Applicable
File nameUpdate.mum
File versionNot Applicable
File size1,823
Date (UTC)17-Sep-2012
Time (UTC)14:40
PlatformNot Applicable
File nameX86_microsoft-windows-rasmprddm_31bf3856ad364e35_6.1.7601.22044_none_9b86c5eb451082f5.manifest
File versionNot Applicable
File size13,628
Date (UTC)04-Jul-2012
Time (UTC)21:57
PlatformNot Applicable