2 of the DNS topmost 13 servers came under attack yesterday, nothing you would have noticed, but it does mean that the American DoD and ICANN have been doing there homework.
The people running the .ORG got attacked as well, but they did not go down at all either
The DOS attacks work by sending requests to servers, and adding the wrong ip for the return address, so the servers would respond to either a non existing address, or to a computer that did not send the request and therefore not expecting an answer, the asymetric attack could either overwhelm the servers, or overwhelms the network in the case of requesting somewhat large chunks of data, since the sender only needs to send a small request, and not worry about having the bandwidth to receive the response.
There is an old saying about that that don’t break us makes us stronger, and it can not be more true than this time, it is a reminder that security should always come first when the internet could go down, and at the same time, nothing really went down.