DDos attack

I know how it works in theory, but I'm curious how do people actually do these ddos attacks. Or more specifically what sort of resources would you need to do a ddos attack on server to keep it down for a couple days?

 

Search google or youtube and you will see exactly how it's done.

 

I heard of someone that ddos'd a site using Facebook. They built an app and gave it away for free but hidden in it was code for ddos'ing someone that had ticked them off.

 

DDoSing can be done in so many different ways as it's all about opening connections.

 

DDoS is a distributed denial-of-service attack.
Most attackers use botnets which consist of compromised by trojans or another way users PC (called zombie).
Management of zombies is provided by issuing commands to them.
For details you can check wikipedia articles about them.

 

Lately, I've seen a lot of DDoS attacks made from PHP Shells, these are just a php file uploaded into compromised servers. They also use them to "kick" xbox players from the games