The rapid development of mobile and wireless communication technologies have led to a new paradigm called the Internet of Things (IoT). Things here refer to all real world entities such as humans, sensors, actuators and all other things which are capable of sending and receiving data in the form of request or response from other devices. IoT enables communication via standard internet connection which is unreliable. IoT devices are resource constrained and they vary widely in size, energy, computing power and memory.IPv6 over Low power wireless personal area networks(6LoWPAN) allows low-end devices to be connected to IPv6 networks. It is the combination of IPv6 features and wireless technology. It is IPv6 header compression protocol and can be easily attacked. To overcome this problem Internet engineering task force (IETF) has introduced another new network layer routing protocol called Routing protocol for low power lossy networks (RPL). RPL is different from traditional routing protocols. It is light weight and rank based routing protocol exposed to different routing attacks which significantly consume network resources and have its impact on overall performance. This paper mainly focuses on routing attacks such as blackhole attack, gray hole attack, worm hole attack, Sybil attack and hello flood attack and its preventive measures in IoT environment. © 2018, Institute of Advanced Scientific Research, Inc. All rights reserved.