Typical VPN Applications
There are three basic applications of VPNs:
- Branch office connection
- Organizational network partnership
- Remote access (mobile users)
With the higher Internet speeds available now to companies, branch office VPN connection isn't that uncommon. At the company I work for, for example, we connected a small 5-person branch office to the main company network by getting the branch business class Internet service and establishing a VPN connection between that branch and the main office.
Organizational network partnerships is less common. Interestingly enough, the same company I work for outsources its financial system off site. The financial system is effectively hosted on a farm of servers outside the my company's network. It was actually located several hundred miles away. To access the outsourced computing services, my company established a partner VPN connection between their network and ours. This VPN connection was established as a tunnel through the Internet. From the perspective of computers on both ends, the VPN tunnel provided a WAN-like (wide area network) link. Note that the subnetworks on both sides don't even use Internet-routable IP addresses! And yet the two networks are able to connect with the aid of VPN technology.
The most common application of VPN technology today is remote access where mobile users connect to their headquarters using their remote access VPN client, their high-speed Internet access, and their laptop. Users typically just need to know their VPN server/concentrator IP address or host name (a name that resolves on the Internet), their network login name and password, and possibly a secure token (which allows for a 2-factor login and authentication). Once they have these essentials, users can setup their VPN client. Starting with Microsoft Windows 2000 the native VPN client is based on the PPTP protocol.