In undergraduate computer networking courses, the ideal scenario involves demonstrating network communications with multiple interconnected computers and a packet sniffer tool. However, practical challenges arise when attempting hands-on exercises, such as accessing or reconfiguring physical computers for online networking practice. Additionally, certain network concepts, like routing and switching, are typically discussed theoretically due to the limitations of observing external network packet transfers and the constraints faced by institutions in maintaining the necessary hardware for hands-on practice. This paper introduces a simulation-based approach to facilitate the teaching and learning of computer networking internals in an online environment, eliminating the need for dedicated hardware devices. The paper outlines various simulation activities and experiments designed to assist instructors in teaching and enable students to explore these internal networking concepts effectively.