Microsoft KB Archive/943378

= After you connect a Windows XP-based computer to the Routing and Remote Access Services server through a virtual private network (VPN) connection, the computer cannot establish more than 32 static routes =

Article ID: 943378

Article Last Modified on 11/8/2007

-

APPLIES TO


 * Microsoft Windows XP Professional

-



SYMPTOMS
Considering the following scenario:
 * On a Windows XP-based client computer, you connect the computer to the Routing and Remote Access Services server through a virtual private network (VPN) connection.
 * You use a Dynamic Host Configuration Protocol (DHCP) server to provide classful static routes for the VPN client computer by configuring the 249 DHCP scope option.
 * You have configured more than 32 routes together with the corresponding 24-bit subnet masks.

In this scenario, the VPN connection is established successfully. However, only 32 routes are added into the routing table on the Windows XP-based VPN client computer. Therefore, you cannot access some network resources.

Notes
 * This problem does not occur on Windows Server 2003-based client computers.
 * This problem does not occur when the subnet masks are set to 8-bit or to 16-bit.



CAUSE
This problem occurs because of a limitation of the buffer that the remote access component (Rasppp.dll) in Windows XP maintains. When the DHCP client service (Dhcpcsvc.dll) passes static routes to the remote access component, the remote access component cannot accommodate more than 32 static routes in the buffer. Therefore, the remote access component truncates the rest of the static routes if the DHCP client service passes more than 32 static routes.



Hotfix information
A supported hotfix is now 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 this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows XP service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or 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. To create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Prerequisites
To install this hotfix, you must have Windows XP Service Pack 2 installed on the computer.

Restart requirement
You do not have to restart your computer after you apply this hotfix.

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

Registry information
To use this hotfix, you do not have to make any changes to the registry.

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 XP with SP2, x86-based versions


STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.



MORE INFORMATION
For more information, click the following article number to view the article in the Microsoft Knowledge Base:

232703 How to use DHCP to provide Routing and Remote Access clients with additional DHCP options

For more information about DHCP options, click the following article number to view the article in the Microsoft Knowledge Base:

121005 DHCP options supported by clients

For more information, 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

Keywords: kbexpertiseadvanced kbfix kbpubtypekc kbqfe kbhotfixserver KB943378

-

[mailto:TECHNET@MICROSOFT.COM Send feedback to Microsoft]

© Microsoft Corporation. All rights reserved.