what is it?
A DDoS (Distributed denial-of-service) attack is when a hacker like Okiver gets control of multiple computers called "zombies", which belong to innocent people. He then tells them to attack a single target, like a Blockland server or hosting service. The zombies are usually infected with some kind of virus which listens for commands from Okiver, and executes them. In this case, he asks them to flood a BL server with a load of random UDP packets, which clogs up the BL server's Internet connection.
Another popular form of DDoS which Blockland services have been hit with is a DrDoS (Distributed reflection denial-of-service) attack. This is a DDoS except the zombie computers are not infected with malware, and they use UDP. Okiver sends a request to the zombie, which we will assume is a network time server. Let's say "71.168.210.93" is the IP address of a hosting service which Okiver wants to attack.
A major weakness of UDP is that a sender can "spoof" the source IP address on a packet of data that they send. They can fake the originating address and make it look like it comes from somebody else. IP spoofing makes it harder to trace the attack back to Okiver.
So Okiver makes the source address "71.168.210.93" instead of his real IP address. Once the network time zombie receives the request, it thinks that the hosting service was the one who requested it. So it sends a very large reply to 71.168.210.93, and as a result, the hosting service's network is clogged up with the bogus replies, and legitimate data cannot flow.
Some popular types of zombie servers which are used to "reflect" requests are DNS, network time, and other game servers.
