System administrators must consider and adequately manage computer security issues, including attacks on a web server. DDoS (Distributed Denial of service) is one of the attacks on a network that can reduce web server performance by flooding network traffic. DDoS sends several data packets simultaneously to drain the target system resources to respond to this data packet. With so many incoming data packets, the web server will experience overload. This research provides an overview of how the performance of an attack called DDoS (Distributed Denial Of Service) is performed. Where the attack burdens webserver traffic so that it cannot be handled/overloaded so that the website cannot be accessed. Later on, Virtualbox will install a Linux-based Ubuntu Operating System; then, the Ubuntu Operating System will try to carry out DDoS attacks on websites and then analyze using Wireshark.