The Internet plays an increasingly important role in the commercial world, just as in our everyday life. During business concerned communication the network security is a must. The technology being introduced provides a reliable solution, which can solve the interconnection of the enterprise networks and grant full access for the remote workers in a secure way. The aim of this dissertation is to give an overview on the IP based virtual private network technologies and prove the functionality through a case study. The reader must be familiar with the information technology and computer network terms and their theoretical operation principle. It is an advantage if the reader also knows something about network security in general. However these terms are explained in the glossary as well.