Distributed Denial of Service (DDoS) attacks today have been amplified into gigabits volume with broadband Internet access; at the same time, the use of more powerful botnets and common DDoS mitigation and protection solutions implemented in small and large organizations’ networks and servers are no longer effective. Our survey provides an in-depth study on the current largest DNS reflection attack with more than 300 Gbps on Spamhaus.org. We have reviewed and analysed the current most popular DDoS attack types that are launched by the hacktivists. Lastly, effective cloud-based DDoS mitigation and protection techniques proposed by both academic researchers and large commercial cloud-based DDoS service providers are discussed.