PRB: IIS May Hang If You Enable ASP Server-Side Script Debugging

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Article ID: 312941 - View products that this article applies to.
This article was previously published under Q312941
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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:
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If you enable Active Server Pages (ASP) server-side script debugging in the Web site configuration and ASP encounters a scripting error, Internet Information Services (IIS) may hang, but no error messages are sent to the client browser.

NOTE: This behavior may occur if you have installed the Microsoft Script Debugger or Microsoft Visual Interdev on a server that is running Microsoft IIS 4.0 or later in a development environment.


This behavior occurs because you have not properly configured the default debugger that is in use.


To resolve this behavior, make the additional configurations that are outlined in the following article in the Microsoft Knowledge Base:
281427 PRB: Microsoft Script Debugger Does Not Break at Error


This behavior is by design.


You should not enable the Enable Server-Side Script Debugging property on a production environment.

The enabling of server-side script debugging causes ASP to run in a single threaded mode; therefore, one thread at a time only executes for each application. Even if you properly configure the Microsoft Script Debugger, this dramatically affects the Web server performance.

When ASP server-side script debugging is enabled, the value for ASP Requests Executing in Performance Monitor will never be more than 1. The value for ASP Requests Queued will grow depending on the number of requests that are made to the server. This is known as "ASP execution serialization".


Article ID: 312941 - Last Review: February 27, 2014 - Revision: 4.1
  • Microsoft Internet Information Server 4.0
  • Microsoft Internet Information Services 5.0
  • Microsoft Internet Information Services 6.0
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