Unlike the teaching of subjects such as operating systems and system administration where a reduced number of computers is required to practice with them (typically two personal Computers—PCs—is enough to set up a scenario), the teaching of computer networks may require a large number of computers, especially when dealing with some advanced concepts. The use of labs based on real equipment has some important disadvantages. More precisely, because there is a single infrastructure that cannot be used by all the students at the same time, the learning process must be organized in small groups of students that will practice in shifts and the time the students can work with the computer network scenario is limited. Conversely, the applications of virtualization techniques in labs are of great benefit because they enable each student to work with his/ her own network scenario. Apart from solving different problems present in labs based on real equipment, virtualization facilitates the practical learning of computer network concepts. First, a key advantage highly appreciated by students is the mobility. Given that students can install the virtualization software in their own computer or laptop, they can work with the computer network scenario either at home or in the university premises. Thus, the students can improve their practice in the computer network scenario and gain in flexibility because they are not constrained to the timetable that is scheduled to work with the different physical components in a real lab. Second, virtualization also offers flexibility and students can design their own network topologies or teachers can create and distribute the scenario that the students will work with (by defining a topology and its components). Finally, also thanks to virtualization, students can gain experience in configuring, deploying and managing tools in realistic topologies that they can find in their future professional activities. In summary, virtualization is a powerful tool that allows students to consolidate the concepts learned in theoretical lessons by practicing in a flexible and realistic environment.