Hands-on lab exercises are important in teaching Computer Networking to undergraduate students since they illustrate how theory and practice are together. Using Kathará, a lightweight network emulator, is a scalable and cost-effective solution. Integrating Kathará into the Computer Networking through a set of proper exercises with different objectives can significantly enhance the teaching and learning performance. Such a kind of work must tackle three main challenges: the diversity of protocols, simplicity of the exercises, and scalability of the networks. Our solution leverages the features of Kathará to make hands-on lab exercises more accessible, reproducible, and customizable for the students instead of asking for a strong background in network programming. Our observation during the teaching process concludes that this hands-on lab facilitates the learning of students from different schools, such as information technology, education, and engineering.