A Distributed Denial of Service (DDoS) attack is an attack in which multiple a computer system attack a target, such as a server, website or other network resource, and creates a denial of service for the legitimate users. The incoming messages, connection requests or malformed packets to the target system that are being flooded forces the victim to slow down or even crash and shut down, thereby service to legitimate users or systems is denied. In this paper, various techniques are studied to analyse mitigation methods in such a way that bot-masters' attack is reduced thereby reducing the Distributed Denial of Service attack. This approach helps the legitimate users to reach the targeted resource without any denial of service. © 2018 IAEME Publication.