Any programmer is interested in securing his website. So I found this http://www.youtube.com/watch?v=DB4eMFrQYiY&feature=youtube_gdata_player which talks about crashing a website using cmd only. How to secure any website against this type of attak. Since anyone can do it which makes things harder.
That video is trying to demonstrate a ping flooding attack, a DoS attack in which he's trying to send more ICMP packets than what the server can handle. Chances are that the server being "attacked" has bigger downlink that the attacker's uplink. Allow me to demonstrate.
The guy in the video is trying to do something like this:
As you can see, he'll never be able to flood the server's downlink/resources. For this attack to be successful you need something called a Distributed Denial of Service attack (DDoS), in which a large number of attackers try to flood the server's resources
To learn about mitigating DDoS attacks, you can start by checking this question about different techniques used by firewalls.