ASP.NET Stress Testing

Is there a way to test an application where you simulate a hundred different clients connecting to a IIS server and asking the same data? At the customer where our project is running they have 400 computers and they often do stress tests with all computers. I on the other hand have only got my laptop... (and a development server).

(In my case the data is asked through a WebORB Gateway).

• HP (formerly Mercury) LoadRunner or Performance Center
• Visual Studio Application Center Test (Enterprise Editions only?)
• Microsoft Web Application Stress Tool (aka WAST, aka "Homer"; predecessor to Application Center Test)
• RadView WebLoad

ab is a tool that was designed for Apache, but you can use it with IIS.

After surveying a lot of open source and paid tools, I found the most success with Microsoft's Visual Studio 2008 Team Suite Test Edition (soon to be part of Visual Studio 2010 Ultimate). It has strong stress testing functionality. Microsoft's free application for stress-testing, WCAT is underpowered and buggy, but the full blown Test Edition goes up against products like LoadRunner but is easier to use, better-integrated with VS/ASP.NET and for much less money per virtual user.

Have a look at StresStimulus.

It integrates very well with Fiddler. The setup and usage is very smooth and it provides a lot of functionality and configuration. My best found when googling for a Web Load Test solution. Fiddler btw is a great tool.