The rapid development of networking technology and the growing importance of networking in business environments make it essential for graduates to gain first-hand experience in realistic networking laboratory. In this paper, we present a computer networking experiment course in the realistic environment. Not only do the students gain a better understanding of networking theoretical knowledge in class, but they also acquire hands-on experience of networking configuration and program. What's more, students can learn to build complex network simulating business environment. We describe experimental environment, experimental activities and implementation of experiments. The course is being offered for third-year undergraduates and first-year graduates.