ab (Apache Benchmark) is a tool for benchmarking your HTTP server. It provides a quick an easy way to evaluate your http serving capabilities. ab overloads the server with http requests and measures the time it takes to serve all those requests.
How to install ab and where to get it? The real thing is that ab comes preconfigured with your apache installation. Apache by himself is just an extension command for the Apache Web Server. So if you have already installed Apache, then you should be able to run ab.
What we need in order to get ab to work is type the command and append the URL address we want to test. The command is issued as follows.
server ~ # ab -n10000 -c8 http://piper/
# Number of connections to send to the server -n
# Number concurrent requests to be made -c
# Option activates the KeepAlive feature -k
# Is the timelimit (in seconds) -t
ab testing mechanism actually is a good example of a Denial of Service (DoS) attack.