  This is the era of smart devices or things which are fueling the growth of
Internet of Things (IoT). It is impacting every sphere around us, making our
life dependent on this technological feat. It is of high concern that these
smart things are being targeted by cyber criminals taking advantage of
heterogeneity, minuscule security features and vulnerabilities within these
devices. Conventional centralized IT security measures have limitations in
terms of scalability and cost. Therefore, these smart devices are required to
be monitored closer to their location ideally at the edge of IoT networks. In
this paper, we explore how some security features can be implemented at the
network edge to secure these smart devices. We explain the importance of
Network Function Virtualization (NFV) in order to deploy security functions at
the network edge. To achieve this goal, we introduce NETRA - a novel
lightweight Docker-based architecture for virtualizing network functions to
provide IoT security. Also, we highlight the advantages of the proposed
architecture over the standardized NFV architecture in terms of storage, memory
usage, latency, throughput, load average, scalability and explain why the
standardized architecture is not suitable for IoT. We study the performance of
proposed NFV based edge analysis for IoT security and show that attacks can be
detected with more than 95% accuracy in less than a second.
