DDoS for hire ” is perfectly legitimate, according to the owner of the site. The site uses a technique called DNS reflection to flood a website and amplify the amount of traffic directed at an address. It seems that the Federal Investigation Bureau uses the site to monitor the activity of users on the network. It is not clear if it is a guy who works with the FBI, but what is certain is that the service is alive and kicking. An FBI spokesman would neither confirm nor deny the claim.
Source: https://thehackernews.com/2013/05/fbi-sponsored-ragebooter-ddos-attack.html