Extra CRLF Character Is Added to a POST Request That Is Sent to an HTTP 1.1 Server

When a POST request is sent to a HTTP 1.1 server, Internet Explorer may append an extra carriage return and line feed character (CRLF) to the end of the post. This may cause problems with the server. The network may stop responding (hang) or you may receive a "Page Not Found" error message, depending on how the server or the Web application is configured.

Note If you suspect that you have this problem, follow the steps in the "Steps to Reproduce the Problem" section to test the problem. If you have this problem, apply the fix that is listed in the "Resolution" section.

This problem occurs because Internet Explorer may incorrectly store gzip compressed pages with the HTTP 1.0 header. If that page is later requested by Internet Explorer, it will read the 1.0 header and it will think that it should send an extra CRLF (in a subsequent POST request). Internet Explorer typically sends an extra CRLF in a POST request when it thinks that it is communicating with an HTTP 1.0-based server.

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. The English version of this fix has the file attributes (or later) 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.

To work around this problem, change the SendExtraCRLF setting in the registry. To do this, follow these steps:

1. Click Start, and then click Run.
2. In the Open box, type Regedit, and then click OK.
3. Locate, and then click the following key in the registry:
   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
4. On the Edit menu, point to New, and then click DWORD Value.
5. Type SendExtraCRLF, and then press ENTER.
6. With SendExtraCRLF selected, click Modify on the Edit menu.
7. In the Value data box, type 0, and then click OK.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.