Microsoft KB Archive/912213

= VPN customers who use L2TP behind a NAT device cannot connect to a Windows Server 2003 SP1-based computer that is running Routing and Remote Access service =

Article ID: 912213

Article Last Modified on 10/11/2007

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APPLIES TO

 Microsoft Windows Server 2003, Datacenter x64 Edition Microsoft Windows Server 2003, Enterprise x64 Edition Microsoft Windows Server 2003, Standard x64 Edition Microsoft Windows Server 2003 SP1, when used with:  Microsoft Windows Server 2003, Datacenter Edition for Itanium-Based Systems

 Microsoft Windows Server 2003, Enterprise Edition for Itanium-based Systems

 Microsoft Windows Server 2003, Datacenter Edition (32-bit x86)</li></ul>

 Microsoft Windows Server 2003, Enterprise Edition</li></ul>

 Microsoft Windows Server 2003, Standard Edition (32-bit x86)</li></ul> </li></ul>

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<div class="notice_section">

<div class="symptoms_section">

SYMPTOMS
Consider the following scenario. Virtual private network (VPN) customers use Layer Two Tunneling Protocol (L2TP) to try to establish a connection to a Windows Server 2003 Service Pack 1 (SP1)-based computer. The computer is running Routing and Remote Access services. In this scenario, the customers receive remote access error 691.

This problem occurs when the following conditions are true:
 * The number of VPN customer connections that are made at the same time exceeds two.
 * Both the Windows Server 2003-based computer that is running the Routing and Remote Access service and the VPN customers are in a network address translation traversal (NAT-T) environment. This means that the VPN customers and the Windows Server 2003-based computer are behind a network address translation (NAT) device.

<div class="cause_section">

CAUSE
This problem occurs because the Internet Protocol security (IPsec) driver is malfunctioning.

<div class="resolution_section">

Service pack information
To resolve this problem, obtain the latest service pack for Windows Server 2003. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

889100 How to obtain the latest service pack for Windows Server 2003

Prerequisites
No prerequisites are required.

Restart requirement
You must restart the computer after you apply this hotfix.

Hotfix replacement information
This hotfix does not replace any other hotfixes.

File information
The English version of this hotfix 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.

Windows Server 2003, x64-based versions
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STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section. This problem was first corrected in Windows Server 2003 Service Pack 2.

<div class="moreinformation_section">

MORE INFORMATION
For more information about standard terminology that is used to describe Microsoft software updates, 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

Technical support for x64-based versions of Microsoft Windows
Your hardware manufacturer provides technical support and assistance for x64-based versions of Windows. Your hardware manufacturer provides support because an x64-based version of Windows was included with your hardware. Your hardware manufacturer might have customized the installation of Windows with unique components. Unique components might include specific device drivers or might include optional settings to maximize the performance of the hardware. Microsoft will provide reasonable-effort assistance if you need technical help with your x64-based version of Windows. However, you might have to contact your manufacturer directly. Your manufacturer is best qualified to support the software that your manufacturer installed on the hardware.

For product information about Microsoft Windows XP Professional x64 Edition, visit the following Microsoft Web site:

http://www.microsoft.com/windowsxp/64bit/default.mspx

For product information about x64-based versions of Microsoft Windows Server 2003, visit the following Microsoft Web site:

http://www.microsoft.com/windowsserver2003/64bit/x64/default.mspx

Keywords: kbbug kbfix kbqfe kbpubtypekc kbwinserv2003sp1fix kbhotfixserver kbwinserv2003sp2fix KB912213

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