What is a VPN? Advantages and disadvantages of OpenVPN

Put simply, a VPN allows an administrator to create a "local" network between mul-
tiple computers on varying network segments. In some instances, those machines
can be on the same LAN, they can be distant from each other across the vast Inter-
net, or they can even be connected across a multitude of connection media such as
wireless uplinks, satellite, dial-up-networking, and so on. The P in VPN comes from
the added protection to make that virtual network private. Network traffic that is
flowing over a VPN is often referred to as inside the (VPN) tunnel, compared to all
the other traffic that is outside the tunnel.

GeoIP / Location-based services: Some websites serve data based on geo-
graphic location by using GeoIP databases and other records. A VPN can
allow you to "bounce" through another machine in a location closer to the
content you really want. Internet video services such as Hulu, YouTube, and
Netflix are common examples of this.
•Bypassing censorship / Political freedom: Some regimes, such as NorthKorea or China, have extraordinarily restrictive censorship rules. The "Great
Firewall of China" is one extreme example. The lockdowns of Internet access
during political uprisings such as the "Arab Spring" attempt to contain and
control reports outside the conflict. VPNs can aid in getting outside those re-
strictive rules to the greater Internet.

Here is an example of the traffic within a VPN. While the VPN itself is routed
across the Internet like in the preceding figure, devices along the network path only
see VPN traffic; those devices are completely unaware of what is being transmitted
inside the private tunnel. Protected protocols, such as HTTPS and SSH, will still be
protected inside the tunnel from other VPN users, but will be additionally uniden-
tifiable from outside the tunnel. A VPN not only encrypts the traffic within, it hides
and protects individual data streams from those outside the tunnel.

Advantages and disadvantages of OpenVPN

Advantages of OpenVPN are its ease of deployment, its configurability, and the abil-
ity to deploy OpenVPN in restricted networks, including NAT'ted networks. Also,
OpenVPN includes security features that are as strong as IPSec-based solutions, in-
cluding hardware token security and support for different user authentication
mechanisms.

Disadvantages of OpenVPN are its current lack of scalability and its dependence on
the installation of client-side software. Another disadvantage is the lack of a GUI for
configuration and management. Notably the tap interface driver for Microsoft Win-
dows has often caused deployment issues when a new version of Windows is re-
leased.