As Internet of things (IoT) continues to entrench into our homes, offices, hospitals, and other walks of life, the stakes are too high to leave security to chance. IoT devices are loosely secured and vulnerable to a number of attacks. One of the most common attacks is the distributed denial-of-service (DDoS) attack. DDoS attacks are easiest to launch and very difficult to defend. Although DDoS is an old Internet attack and a number of defenses are available but a large number of new, constrained and always on IoT devices have increased the attack surface beyond imagination. Earlier, defending DDoS in IoT continued to torment researchers as well as enterprises. This review paper unveils how IoT offers a second chance to improve DDoS defenses and provides a survey of such mechanisms with respect to technologies that drive the IoT protocol stack like IPv6, RPL, IEEE 802.15.4, 6LoWPAN, and CoAP.