Files with the .map Extension Are Restricted to 128 KB in IIS

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This article was previously published under Q251219

We strongly recommend that all users upgrade to Microsoft Internet Information Services (IIS) version 7.0 running on Microsoft Windows Server 2008. IIS 7.0 significantly increases Web infrastructure security. For more information about IIS security-related topics, visit the following Microsoft Web site:

http://www.microsoft.com/technet/security/prodtech/IIS.mspx (http://www.microsoft.com/technet/security/prodtech/IIS.mspx)

For more information about IIS 7.0, visit the following Microsoft Web site:

http://www.iis.net/default.aspx?tabid=1 (http://www.iis.net/default.aspx?tabid=1)

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SYMPTOMS

If a file is larger than 128 KB and has the .map extension, you may receive one or more of the following error messages in the browser:

HTTP 500 - Internal server error

-or-

HTTP/1.1 500 Server Error

-or-

Network request is not supported

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CAUSE

The ".map" extension is reserved and intended for association with server-side image maps in Internet Information Server (IIS) and Internet Information Services (IIS). The size of these image maps is restricted to 128 KB. IIS enforces this size limit on all files that have a file name extension of .map before it loads the files.

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