The Internet of things (IoT) is the inter-networking of physical devices, vehicles (also referred to as “connected devices” and “smart devices”), buildings, and other items embedded with electronics, software, sensors, actuators, and network connectivity which enable these objects to collect and exchange data. Internet of Things (IoT) is a fast-growing innovation that will greatly change the way humans live. It can be thought of as the next big step in Internet technology. The changing operating environment associated with the Internet of Things represents considerable impact to the attack surface and threat environment of the Internet and Internetconnected systems. IoT is heterogeneous system consisting of various types of sensors nodes or devices with different kind of technology at each layer. However, due to the limited address space of IPv4, an object in the IoT uses IPv6 to accommodate space in Internet. Objects in the IoT can be devices with sensory capabilities, smart metering, health care sensor etc.[1] As wireless devices become increasingly pervasive and essential in our daily life, security becomes a critical issue. These inchoate devices and technologies are prone to more threats in future, if not governed adequately. 6LoWPANbased IoT has inherited deficiencies: limited resources in terms of power, processing, memory, space and unreliable communication with respect to packet loss rate, collisions.[2] An adversary can take advantage of these weaknesses to initiate different kinds of attacks. More specifically, denial-of-service (DoS) attacks are considered to have adverse effects in disrupting WSNs’ communication; still, effective security mechanisms against DoS attacks are yet to be addressed. This paper studies the vulnerabilities present in IP-based WSNs with a major focus on DoS attacks and analyses the existing solutions and countermeasures. Finally, it presents novel security architecture for detecting DoS attacks in 6LoWPAN-based IoT. The proposed solution is actually integrated within the platform being developed in the ebbits project [3]. Such project aims to semantically integrate the IoT into mainstream enterprise systems and support interoperable, online end-to-end business applications. [4] In fact, the networking features exposed by the ebbits platform are opportunistically exploited to improve the performance of the proposed detection solution.