DOCUMENT:Q247249  31-JUL-2001  [iis]
TITLE   :Error Message: HTTP/1.1 Error 400 - Bad Request
PRODUCT :Internet Information Server
PROD/VER:winnt:5.0
OPER/SYS:
KEYWORDS:kbOSWin2000 kbiis500prod2web kbhttp400 kbProd2Web

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The information in this article applies to:

 - Microsoft Internet Information Services version 5.0 
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SYMPTOMS
========

When a GET request is submitted to a Web server configured with Custom Error
pages, the Web server sends the following error message to the client browser:

   HTTP/1.1 Error 400 - Bad Request

CAUSE
=====

This behavior is expected when the GET request itself cannot be parsed because
of some kind of packet corruption. If you send a bad request to the IIS Web
server, the Custom Errors functionality is not invoked, which causes the
"HTTP/1.1 Error 400 - Bad Request" error message.

RESOLUTION
==========

If the contents of a GET request are corrupt, then the server is unable to
determine the URL or the host to which the GET request should be sent. IIS is
unable to retrieve the host information from the GET request packet in order to
look up the meta data for the custom error. This is by design. Errors that
result from severely corrupted GET requests are not customizable.

To more completely determine what may be occurring, obtain a network capture of
the communication packets between the client receiving the error and the Web
server itself. Use the Microsoft Network Monitor utility to capture network
packets for analysis. For additional information, click the article number below
to view the article in the Microsoft Knowledge Base:

   Q148942 How to Capture Network Traffic with Network Monitor

Additional query words:

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Keywords          : kbOSWin2000 kbiis500prod2web kbhttp400 kbProd2Web 
Technology        : kbiisSearch kbiis500
Version           : winnt:5.0
Issue type        : kbprb

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