Web server stress testing tool

I am looking for a free web server stress testing application/tool/website. I have used Paessler Webstress, it is good enough, but only free with restricted functionality.

From web app igor

• Have you looked at Apache JMeter? It is software.

  I am not aware of any legal stress testing tools as a web-app, though if you are desperate, you can try renting those spambots machines (joking).

  There is a couple of services that do single/double retrieval with detailed statistics. This might be useful to do while you are using JMeter to simulate the rest of the load. See, for example, WebPageTest

  igor : +1 thanks, good joke (I will think about it...joke)
  From Alexandre Rafalovitch

• As for me, I prefer LoadImpact.

  igor : +1 will try, thanks!
  From Kavu

• Yes Apache Jmeter is perfect. I had used it extensively in last 3 months. Here are some good posts to get you started on Apache Jmeter Apache Jmeter

  igor : +1 a real experience and a reasonable help are welcome!
  From vinay

• Badboy is an application I have used in the past to do some load testing, Its a bit complicated but extremely powerful.

  igor : +1 it seems as a good tool. i will investigate it. thank you!

  igor : While Badboy offers some elementary load testing features, to do real stress testing you often need much more. Rather than trying to offer all of the features of a complete load testing product, Badboy integrates with a free, open source product called JMeter. JMeter is run by the Apache Software Foundation and is free and open source.
  From d1k_is