Testing servers to monitor their capacity and capability to handle multiple connections is a difficult task to achieve manually. Sure, you could have 100 people all pressing Return at the same time, but you couldn't adequately test the response times to be able to use that information.
The Web Capacity Analysis Tool (WCAT) can do this for you by submitting multiple requests to a server and timing the responses, thereby testing the server loading and availability under heavy loads. For more in-depth tests, you can run the tool on a number of machines simultaneously and increase the overall load.
Unfortunately, I don't have the space to cover the tool in detail in this appendix, so check the extensive documentation for more information.
WHAT'S YOUR CAPACITY?
I always try to test my Web sites' capacities before placing a new site into production. Knowing how much traffic the site can handle is a great piece of administrative information that will help you plan for the site's growth.