Article ID: 904825
Article Last Modified on 12/4/2007
APPLIES TO
- Microsoft Internet Security and Acceleration Server 2004 Enterprise Edition
- Microsoft Internet Security and Acceleration Server 2004 Standard Edition
- Microsoft Internet Security and Acceleration Server 2000 Service Pack 1, when used with:
- Microsoft Internet Security and Acceleration Server 2004 Standard Edition
SYMPTOMS
Consider the following scenario. You publish a virtual private network (VPN) server that uses Point-to-Point Tunneling Protocol (PPTP) in Microsoft Internet Security and Acceleration Server (ISA) 2004. You apply the Requests appear to come from the ISA server computer server publishing rule in ISA Server 2004 to enable server publishing even when the published server is not a Secure Network Address Translation (SNAT) client. In this scenario, VPN connections time out during the user-name and password verification stage. Therefore, VPN clients cannot connect to the PPTP VPN server.
Note You may not experience these symptoms if the published server is configured as a SecureNAT client of the ISA Server computer.
CAUSE
PPTP connections use the Generic Route Encapsulation (GRE) protocol to encapsulate data. The encapsulated data is added to a GRE packet that carries the data between two tunnel end points.
When you apply the Requests appear to come from the ISA server computer server publishing rule, ISA Server 2004 must translate the IP address of these packets into the IP address of the ISA Server computer.
This problem occurs because the IP address of the GRE packets is not translated in compliance with the publishing rule. Therefore, the VPN connection times out.
RESOLUTION
ISA Server 2004, Enterprise Edition and ISA Server 2004, Standard Edition
Service pack information
To resolve this problem, obtain the latest service pack for Internet Security and Acceleration Server 2004. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
891024 How to obtain the latest ISA Server 2004 service pack
Hotfix Information
To resolve this problem, obtain the latest service pack for ISA Server 2004. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
891024 How to obtain the latest ISA Server 2004 service pack
ISA Server 2004, Standard Edition
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 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:
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:
Prerequisites
To install this hotfix, you must have ISA Server 2004, Standard Edition Service Pack 1 (SP1) installed on your computer.
Restart information
You must restart your 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 tool in Control Panel.
| File name | File version | File size | Date | Time | Platform |
|---|---|---|---|---|---|
| Fweng.sys | 4.0.2163.277 | 340,192 | 08-Aug-2005 | 05:08 | Not Applicable |
| Pptpfltr.dll | 4.0.2163.277 | 65,248 | 08-Aug-2005 | 05:08 | x86 |
| Wspsrv.exe | 4.0.2163.277 | 935,136 | 08-Aug-2005 | 05:08 | x86 |
STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Internet Security and Acceleration Server 2004 Service Pack 2.
MORE INFORMATION
For more information about how to install ISA Server 2004 hotfixes and updates, click the following article number to view the article in the Microsoft Knowledge Base:
885957 How to install ISA Server hotfixes and updates
For more information about the 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
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