The internet is faced with many problems daily, one of them is decrement in network bandwidth because of Distributed Denial of Service (DDoS) attack on host server, which deplete host resources. Researchers has been invented many protection mechanisms such as detection, trace back, prevention, reaction, and characterization are in case of DDoS attacks, which will control the number of malicious packets received by the victim. But it does not provide efficient detection technique with high rate in real time network infrastructure. Thus, modern technologies are prepared on Mininet network simulators, which give more impact to simulate the real network. The architecture of Software Defined Networks (SDN) and OpenFlow architecture is used to demonstrate a programmable network model and centralized management of real network. In this research work, we provide design of software defined network (SDN) using mininet simulator and security issues related to the Software Defined Network.