FIX: "HTTP 400 - Bad request" error message in the .NET Framework 1.1


When you run the Microsoft .NET Framework 1.1, and then you visit a URL that contains a second colon (":"), you receive the following error message:
1.1 - HTTP 400 - Bad Request
For example, the following URL generates this error message:
Note You may also receive this error message if the URL contains the following characters:
* % &


Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone 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.

Registry information

To enable this fix, set the following registry key:
DWORD HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ASP.NET VerificationCompatibility = 1

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.
   Date         Time   Version       Size       File name
07-Aug-2003 10:07 1.1.4322.931 253,952 Aspnet_isapi.dll
07-Aug-2003 10:07 1.1.4322.931 20,480 Aspnet_regiis.exe
07-Aug-2003 10:07 1.1.4322.931 32,768 Aspnet_wp.exe
27-May-2003 09:00 33,522 Installpersistsqlstate.sql
27-May-2003 09:00 34,150 Installsqlstate.sql
07-Aug-2003 10:07 1.1.4322.931 94,208 Perfcounter.dll
07-Aug-2003 10:01 1.1.4322.931 1,216,512 Sy52106.dll
07-Aug-2003 10:01 1.1.4322.931 323,584 System.runtime.remoting.dll
07-Aug-2003 10:01 1.1.4322.931 1,253,376 System.web.dll
07-Aug-2003 10:01 1.1.4322.931 819,200
07-Aug-2003 10:01 1.1.4322.931 569,344
07-Aug-2003 10:01 1.1.4322.931 1,335,296 System.xml.dll
25-Apr-2003 13:32 14,472 Webuivalidation.js

Service pack information

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows

To browse URLs that contain the characters that are mentioned in the "Symptoms" section, obtain the latest service pack for the Microsoft .NET Framework 1.1. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

885055 How to obtain Microsoft .NET Framework 1.1 Service Pack 1

Registry information

Important If you enable this fix, you increase the attack surface of the application. You should not enable this fix unless the application requires it.

After you install the service pack, set the following registry key to enable the fix:
DWORD HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ASP.NET VerificationCompatibility = 1


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 the .NET Framework 1.1 Service Pack 1.

More Information

For more information about software update terminology, 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


Article ID: 826437 - Last Review: Mar 15, 2008 - Revision: 1