| Introduction to VPN
World without VPN
Fig 1.1 so-called "Network" with two computers
As time and technologies advances, networks with several computers (called terminals or workstations), servers and other resources (printers, scanners, etc.) in organizations were formed. This kind of network (called LAN nowadays) is set up to share data and resources among computers within the network (fig.1.2). At this moment, most networks were physically separated from each other, and no equipment was set up to connect external network.
Fig 1.2 Early LAN with 4 workstations and a hub
In the late1980s', the time that the term "internet" had started
to be popular for every computer users and organizations, routers were
always installed in the LAN to connect the internal network with internet
Fig 1.3 Typical LAN with router for internet access
During 1990s', internet is so popular that everyone and every businesses are both talking about advertising on it for good. But the concern of internet security has also become so acute. Firewalls are therefore installed in many networks to provide some degree of security (Fig 1.4).
Fig 1.4 LAN with router and firewall to control external access