Firewall client conflict with third-party layered service providers causes connectivity problems

After you install a third-party program, such as the New.net and Babylon clients, on a computer that is running the Internet Security and Acceleration (ISA) Server Firewall client software, you may experience problems with network connectivity, slow loading of the operating system and error messages on blue screens or STOP error messages. The same problem may also occur if the ISA Server Firewall client is installed after the third party client or provider.

The problem can be caused by the incompatibility of the ISA Firewall client files and some third-party Layered Service Providers. The problem occurs even if the ISA Firewall client is installed following another third-party Layered Service Provider because the ISA Firewall client copies the ProtocolChain member from the last TCP/IP provider it finds on the computer. This causes the proxy provider to be considered a "layered" provider instead of a base provider.

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 this specific problem.

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, submit a request to 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 Web site: 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. The English version of this fix should have the following file attributes or later:
NOTE: The hotfix should be applied on the ISA Server computer, and the ISA Firewall client should be removed and reinstalled from the mspclnt share of the ISA server to update the client software.

This problem occurred with version 2.98 of the New.net Client. (Version 2.98 was released June 19, 2001.) The problem was created by the Microsoft ISA Firewall client and was corrected by Microsoft in this hotfix. However, New.net also published a workaround in New.net Client version 3.36. The New.net workaround prevents the problem on any systems that have not been updated with the Microsoft hotfix. (New.net Client version 3.36 was released December 5, 2001.)

To work around this problem if the third-party clients are not required, remove them from the computer to restore normal functionality. If you cannot start the computer, start the computer in "Safe mode without networking support" mode. Note that using the Add/Remove Programs tool in Control Panel for these programs may not completely uninstall them. If this happens, see the instructions on the following New.net Web site for information about how to remove their client: Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.

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

The ISA Server Firewall client diagnostic utility (Chkwsp32.exe) may be used to troubleshoot this problem, and it may report that the client is not the first layered service provider. You can also use the Sporder.exe utility to see the chainlen parameter. You can download the New.net Client from the following Web site: Note that the New.net client is automatically included with the iMESH client that you can download from the following Web site: The Babylon client is available from the following Web site: Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.

The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.