Distributed denial of service (DDoS) attacks are one of the most important attacks due to reducing the performance of computer networks nowadays. In recent years, the number of devices connected to the internet has been increasing. These devices are not only computers, but also objects of everyday use. The concept of internet has accelerated the increase considerably. Therefore, many problems arise in terms of DDoS attacks. One of them is low-rate DDoS attacks. While high-rate DDoS attacks are often performed with computers, low-rate DDoS attacks can be easily performed by computers and internet-connected objects. Therefore, effective defense mechanism against both attacks must be developed. In this study, new approaches are proposed to filter mixed high-rate DDoS and low-rate DDoS attacks. The ns-2 simulation tool was used to evaluate the performance of the proposed methods. Experimental results show that the proposed methods are successfully filtered mixed DDoS attacks.