IIS: Headers Containing White Spaces May Return a 404 Error

ID: Q199806

The information in this article applies to:

Microsoft Internet Information Server version 4.0

SYMPTOMS

If a request to an Internet Information Server (IIS) Web server contains a "HOST:" entry that contains a space between the HOST and the colon (HOST :), the Web server will return a 404 error message (not found). This information is found in the headers of the request sent by the browser to the Web server. This problem does not occur with a standard browser (Netscape or Internet Explorer).

CAUSE

All "headername:" information presented to Internet Information Server (including 'host:') is assumed to not contain a space. There is no HTTP error code for "Server Not Found," therefore the server returns a 404 error message.

Additional query words:

Keywords : prodNT4OP
Version : winnt:4.0
Platform : winnt
Issue type : kbprb