Distributed Denial of Service (DDoS) attack is one of the biggest threats in Software Defined Internet of Things (SDIoT) environment. Here, we developed a proof-of-concept SDIoT testbed for DDoS attacks using Mininet Emulator. DDoS attack makes the victim’s system unavailable by exhausting the system resources. For testing and proposing a solution for a DDoS attack in a SDIoT environment a testbed must be created. In our study, the testbed was created using VMware workstation, Mininet emulator, OVS switch, and Pox controller. Hping 3 tool for generating attacks, python scripts for custom topologies, Shell script for traffic capturing were used. With varying payloads, RTT (Round Trip Time), throughput and packet loss were calculated. The experimental result show that Mininet is feasible and convenient, and we conclude with a comparison between simulators and emulators providing SDIoT, along with a summary of advantages and disadvantages of using Mininet emulation in a SDIoT environment.