Introduction

This article describes an issue in which you cannot connect to an L2TP/IPsec server behind a NAT-T device in Windows Embedded Compact 7. An update is available to resolve this issue. Before you install this update, all previously issued updates for this product must be installed.

Symptoms

Consider the following scenario:

  • You have network address translation (NAT) and virtual private network (VPN) enabled on a device that is running Windows Embedded Compact 7.

  • You create a VPN (L2TP/IPSec) connection from the Network and Dial-up connection item on this device.


In this scenario, after you connect to the VPN server from this device, you cannot connect to an L2TP/IPsec server behind a NAT-T device.

Resolution

To resolve this problem, install this update. After this update is installed, you can use the new AssumeUDPEncapsulationContextOnSendRule value in the registry to support connecting to an L2TP/IPsec server behind a NAT-T device on a Windows Embedded Compact 7 based device.

The AssumeUDPEncapsulationContextOnSendRule value is located under the following registry subkey:

HKEY_LOCAL_MACHINE\Comm\L2TP1\Parms
You can configure the following values:

  • If you set the AssumeUDPEncapsulationContextOnSendRule value to 0, the device cannot establish security associations with servers that are located behind NAT devices. This is the default value.

  • If you set the AssumeUDPEncapsulationContextOnSendRule value to 1, the device can establish security associations with servers that are located behind NAT devices.

  • If you set the AssumeUDPEncapsulationContextOnSendRule value to 2, the device can establish security associations if both the server and the device are behind NAT devices.

You also need to configure the following registry setting in your OSDesign.reg file. This allows the system to check the AssumeUDPEncapsulationContextOnSendRule value.

; Deleting registry value of "UseIPSec" which is configured in common.reg by following setting

[HKEY_LOCAL_MACHINE\Comm\L2TP1\Parms]
     "UseIPSec"=-

Software update information

A supported software update is now available from Microsoft as Windows Embedded Compact 7 Monthly Update (April 2015).

Note This Windows Embedded Compact 7 Monthly Update is available for download from the following Microsoft Download Center website:

Windows Embedded Compact 7 Updates

Prerequisites

This update is supported only if all previously issued updates for this product are already installed.

Restart requirement

After you apply this update, you must perform a clean build of the whole platform. To do this, use one of the following methods:

  • On the Build menu, click Clean Solution, and then click Build Solution.

  • On the Build menu, click Rebuild Solution.

You do not have to restart the computer after you apply this software update.

Update replacement information

This update does not replace any other updates.

 

The English version of this software update package has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Files that are included in this update package

File name

File size

Date

Time

Path

L2tp.lib

2,251,132

06-Nov-2014

10:18

Public\Common\Oak\Lib\Mipsii\Checked

L2tp.lib

1,969,520

06-Nov-2014

10:18

Public\Common\Oak\Lib\Mipsii\Retail

L2tp.lib

2,439,944

06-Nov-2014

10:17

Public\Common\Oak\Lib\Mipsii\Debug

L2tp.lib

2,302,466

06-Nov-2014

10:18

Public\Common\Oak\Lib\Armv6\Checked

L2tp.lib

1,990,908

06-Nov-2014

10:19

Public\Common\Oak\Lib\Armv6\Retail

L2tp.lib

2,507,922

06-Nov-2014

10:17

Public\Common\Oak\Lib\Armv6\Debug

L2tp.lib

2,116,054

06-Nov-2014

10:17

Public\Common\Oak\Lib\X86\Checked

L2tp.lib

1,843,594

06-Nov-2014

10:17

Public\Common\Oak\Lib\X86\Retail

L2tp.lib

2,176,568

06-Nov-2014

10:17

Public\Common\Oak\Lib\X86\Debug

L2tp.lib

2,090,094

06-Nov-2014

10:18

Public\Common\Oak\Lib\Sh4\Checked

L2tp.lib

1,872,174

06-Nov-2014

10:18

Public\Common\Oak\Lib\Sh4\Retail

L2tp.lib

2,236,332

06-Nov-2014

10:18

Public\Common\Oak\Lib\Sh4\Debug

L2tp.lib

2,253,872

06-Nov-2014

10:18

Public\Common\Oak\Lib\Mipsii_fp\Checked

L2tp.lib

1,972,394

06-Nov-2014

10:18

Public\Common\Oak\Lib\Mipsii_fp\Retail

L2tp.lib

2,442,812

06-Nov-2014

10:17

Public\Common\Oak\Lib\Mipsii_fp\Debug

L2tp.lib

2,290,340

06-Nov-2014

10:18

Public\Common\Oak\Lib\Armv7\Checked

L2tp.lib

1,983,220

06-Nov-2014

10:18

Public\Common\Oak\Lib\Armv7\Retail

L2tp.lib

2,498,612

06-Nov-2014

10:17

Public\Common\Oak\Lib\Armv7\Debug

L2tp.lib

2,302,474

06-Nov-2014

10:18

Public\Common\Oak\Lib\Armv5\Checked

L2tp.lib

1,990,916

06-Nov-2014

10:18

Public\Common\Oak\Lib\Armv5\Retail

L2tp.lib

2,508,788

06-Nov-2014

10:17

Public\Common\Oak\Lib\Armv5\Debug

References

Learn about the terminology that Microsoft uses to describe software updates.

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