An introduction to the devices (especially personal computing devices, switches, routers, servers, and controllers) and protocols (TCP/IP) that form the internet. Through hands-on lab and simulation work, students will build and configure scalable computer networks, embedding secure design principles at every stage. Each week students will be given access to hardware, software, and cloud tools to build illustrative small models of larger networks. A core feature of the course is its integration with "Cyber Defense and Ethical Hacking." Students will not only construct network infrastructures but also see them tested and attacked by peers in the companion course, gaining valuable feedback and insights on the effectiveness of their designs under real-world threat conditions. By the end of this course, students will be equipped to design, defend, and iterate on infrastructure in adversarial conditions, gaining a deep understanding of the technical and human dimensions of cybersecurity.