Internet of Things (IoT), a revolution in the ordinary life of people, transforming the global IT landscape, the development strategy of different types of businesses in various sectors and much more. Due to the various flaws like limited energy, low processing power, lossy wireless links, constrained storage of the IoT devices; it’s the need of the hour that security should be the trivial enabler of IoT. Till date, no silver bullet exists that can effectively implement security in IoT on devices. The closed source security solutions do not help to inculcate security in IoT so that they can communicate securely. The proposed system aims at the implementation of security for authentication and communication of the constrained as well as non-constrained devices in a network. The communication between the devices is established through a proxy server. Depending on various factors like timestamp, the developed application using .net framework detects and blocks the access to the attacker.