In recent years enhancing the capability of network services automatically and dynamically through SDN and CDN/CDNi networks has become a new field of research. These future network architectures pose both a blessing and a threat in the network field. Such network architectures can optimize the overall network services by analyzing the topology, traffic paths, packet handling and so on and also can create a potential target for spoofed IP attacks. We, therefore, propose an architecture for an SDN based CDNi network to detect spoofed ip and create a defense against attacks created by them. We also propose ALTO like servers in our architecture which enable mapping a very big network to provide a summarized view. In the ALTO server we propose an additional map named the mark map as a mechanism to detect spoofed IP addresses. SDN switches are utilized to extract rules associated with the ALTO server mark map and follow a mechanism of spoofed IP detection fed to them by the SDN controller application layer.