When vpn first became popular, it usually require the installation of a dedicated vpn client that bound itself to your computer and its network adapters. It would create a virtual adapter that would allow attachment to the remote network via a separately assigned IP address generated by the firewall the vpn client attached itself to. A newer form of vpn involved the simple action of using a web browser to access a web site. This web site then challenges you to provide a user name and password. Once authentication is complete, access to network resources is possible through the browser using the secure connection that has been created.
There are also modern twists on vpn technology that can let even smart phones connect to a corporate network. Some firewall manufacturers offer the capability for mobile devices to download and install a client that can then tunnel in to the firewall. Once connected, a smart phone is capable of running a remote desktop client, allowing the remote control of a computer inside the company network from anywhere the mobile device is able to make a connection.
The ability to use vpn to gain access to corporate network resources grows as new technology grows providing more opportunities for vpn to take advantage of. As more devices gain the ability to communicate over the internet, the more chances there will be to expand what devices can take advantage of vpn and allow access to work resources. Of course, there will always be a place for and the need for traditional vpn clients and connections, as they offer the most complete and robust method of simulating total presence inside the corporate network. Once a classic vpn client is launched and a computer has attached, it operates essentially as if it were plugged in inside the network.