Started in the early 2000s, the Software Defined Networking (SDN) paradigm has become the backbone for various network based technologies. It has the advantage of being simple to manage and easy to add new features to the network. In comparison to legacy hardware-based networks, scalability, performance, and maintainability become more advanced. However, hackers are more likely to target the SDN, putting the entire network at risk. Denial of Service is a common example of such a threat. It is feasible to reduce such attacks by carefully planning and building the SDN controller as well as the network applications that administer the SDN. This paper presents a novel and efficient method applicable to various types of protocol based Distributed Denial of Service (DDoS) attacks in SDN/OpenFlow networks. It can be used to detect and mitigate Transmission Control Protocol (TCP) SYN attacks, Internet Control Message Protocol (ICMP) ping flood attacks and User Datagram Protocol (UDP) flood attacks that happen against the SDN devices and/or any host. This feature stands above the controller and conforms to the OpenFlow policy without leveraging additional devices. All the detection and mitigation are done based on a True Host list which is created by tracking the Address Resolution Protocol (ARP) requests and replies from hosts. As ARP protocol is necessarily used by all hosts, this method can be effectively utilised for true host list creation and further attack detection and mitigation