Accessing company networks and servers from outside of the company headquarters, too, is becoming more and more important. Reasons for this include advanced division of work and the accelerated geographic fragmentation of workplaces (partly caused by the globalisation). Data transmission and communication in public networks like the Internet are normally not encrypted, meaning they can be read by third parties too. The data and communication of a company, however, are essentially sensitive. Therefore, a secure connection and transmission are indispensable. With a VPN, encrypted connections are set up that can access a protected area. When using SSL certificates, an arbitrary number of persons can use usually the encrypted connection. A VPN is restricted to a select group of people from the outset, the VPN participants.

The concrete use cases vary. A common use case is the so-called site-to-end connection, which is used if employees need to access the company network, e. g. from their home office or from a hotel. In this case, the VPN participant connects to the Internet and starts a VPN software, the VPN client. The VPN client replicates the configuration of the company network virtually on the local computer of the employee. Using the existing Internet connection, it opens a tunnel to the VPN gateway of the company computer and gains access to the company network after successful authentication of the employee.

In case of an end-to-end connection, the computer of the employee does not log in to a remote company network, but connects directly to a server within the company. It thus gains secured access to the server and can for example access the database on the server or a server administration application. If the local networks of several offices, stores or similar are connected via the Internet using a VPN, this is called a site-to-site connection.

Knipp uses »Remote VPN IPSec Clients« by Juniper Networks, which are based on the »IPSec« protocol, as can be seen from the name. The user of the IPsec Client Software opens a secure connection that is encrypted using the Triple DES standard. Additionally, the IPsec Client by Juniper Networks offers a software firewall (also known as personal or desktop firewall) for the user's computer.