A request that contains one or more leading zeros in a port number is rejected by IIS 6.0 on a Windows Server 2003 server

Consider the following scenario:

• A Web client sends a request to Internet Information Services (IIS) 6.0.
• IIS 6.0 is running on a Windows Server 2003-based server.
• The request specifies a port number that contains one or more leading zeros.

In this scenario, the request is rejected. Additionally, you receive the following error message:Note This issue does not occur if the same request is sent to IIS 5.0.

In IIS 6.0, the HTTP protocol stack denies any request that specifies a port number that has one or more leading zeros.

Hotfix information

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. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

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, contact 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.

Prerequisites

You must have Windows Server 2003 Service Pack 1 or Windows Server 2003 Service Pack 2 installed on the Windows Server 2003-based server.

Restart requirement

You have to restart the 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 Server 2003 with SP1, x86-based versions

Windows Server 2003 with SP2, x86-based versions

Windows Server 2003, x64-based versions

Windows Server 2003 with SP2, x64-based versions

Windows Server 2003 with SP1, Itanium-based versions

Windows Server 2003 with SP2, Itanium-based versions

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

Many applications automatically remove leading zeros from the port number of an HTTP request. These applications include Internet Explorer. Therefore, to reproduce this issue, you must manually create an HTTP request that has leading zeros in the port number.

You can use a tool such as Fiddler to create the HTTP request. To download Fiddler, visit the following Web site: This issue frequently occurs when a third-party or custom application sends an HTTP request that has leading zeros in the port number to the server that is running IIS 6.0.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:
The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.

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.