SYMPTOMS
After you configure Microsoft Internet Security and Acceleration (ISA) Server 2004 to filter HTTP content based on signatures or on extensions, users in your organization experience the following symptom.
When a user visits certain URLs, that user receives the following error message in the Web browser:
Error Code 502: Proxy error. The parameter is incorrect. (87)
If you remove all signatures and extensions from the HTTP Filter settings, and if you configure the HTTP Filter component to allow all signatures and extensions, you no longer experience this problem.
Note For more information about how to configure the ISA Server 2004 HTTP Filter component, see the "More Information" section.
RESOLUTION
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
A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next ISA Server 2004 service pack that contains this hotfix.
To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:
Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.
Prerequisites
If you are running ISA Server 2004, Standard Edition, you must have ISA Server 2004 Service Pack 1 installed to apply this hotfix.
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
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 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.ISA Server 2004, Standard Edition
Date Time Version Size File name
---------------------------------------------------------
31-Mar-2005 18:22 4.0.2163.251 120.320 HTTPFilter.dll
ISA Server 2004, Enterprise Edition
Date Time Version Size File name
---------------------------------------------------------
03-Apr-2005 14:00 4.0.3440.251 128.792 HTTPFilter.dll
WORKAROUND
To work around this problem, configure the options on the
Signatures tab and on the
Extensions tab of the HTTP Filter settings. To do this, follow these steps:
- Remove all the signatures and extensions that are listed on these tabs.
- Configure the HTTP Filter to allow all signatures and extensions.
For more information about how to configure the ISA Server 2004 HTTP Filter component, see the "More Information" section.