VPNs
Without getting too technical, a virtual private network ( VPN )is a technology that allows a main computer network (say of a private organization or company) to extend its boundaries beyond its physical boundaries using hardware that understands certain communication protocols (PPTP, IPSec, L2TP) that allow it to tunnel through another network/circuit (typically the Internet) to its remote extension directly to a client or another network.
Typical VPN Applications:
- Branch office connection.
- Organizational network partnership.
- Remote access (mobile users).
How VPNs Work??
By Jeff Tyson and Stephanie Crawford (www.howstuffworks.com).
Analogy: Each LAN is an Island
" Let's Imagine that you live on an island in a huge ocean. There are thousands of other islands all around you, some very close and others farther away. And let's say that each island represents a private local area network (LAN) and the ocean is the Internet. Traveling by ferry is like connecting to a Web server or other device through the Internet. You have no control over the wires and routers that make up the Internet, just like you have no control over the other people on the ferry. This leaves you susceptible to security issues if you're trying to connect two private networks using a public resource.
Continuing with our analogy, your island decides to build a bridge to another island so that people have an easier, more secure and direct way to travel between the two islands. It is expensive to build and maintain the bridge, even if the islands are close together. However, the need for a reliable, secure path is so great that you do it anyway. Your island would like to connect to yet another island that is much farther away, but decides that the costs are simply too much to bear.This scenario represents having a leased line. The bridges (leased lines) are separate from the ocean (Internet), yet are able to connect the islands (LANs). Companies who choose this option do so because of the need for security and reliability in connecting their remote offices.
So how does a VPN fit in? Using our analogy, suppose each inhabitant on your island has a small submarine. Let's assume that each submarine has these amazing properties:Although they're traveling in the ocean along with other traffic, the people could travel between islands whenever they wanted to with privacy and security.
- It's fast.
- It's easy to take with you wherever you go.
- It's able to completely hide you from any other boats or submarines.
- It's dependable.
- It costs little to add additional submarines to your fleet once you've purchased the first one.
That's essentially how a VPN works."
Types of VPNs:
1) Remote access VPNs
These are user-to-LAN connections used when employees of a company who are in remote locations need to connect to the company's private network. A company that wants to set up a remote-access VPN usually outsources to an ESP or enterprise service provider. The ESP sets up a NAS (network access server) and also provides remote users with the software they need for their computers. Then users simply dial the NAS using a toll-free number and access the network via their VPN client software. VPNs offer a good third-party service for encrypted, secure connections between remote users within a private network.
The other two types of VPN are both site-to-site, meaning that multiple fixed sites are connected over a public network (like the Internet):
2) Intranet (password-protected site for company employees)-based VPN
connects LAN to LAN when a company wants to connect multiple remote connections in one private network.
3) Extranet - based VPN
connects LAN to LAN between multiple companies (such as customers and suppliers) so that they can work in a
shared environment.
1) Remote access VPNs
These are user-to-LAN connections used when employees of a company who are in remote locations need to connect to the company's private network. A company that wants to set up a remote-access VPN usually outsources to an ESP or enterprise service provider. The ESP sets up a NAS (network access server) and also provides remote users with the software they need for their computers. Then users simply dial the NAS using a toll-free number and access the network via their VPN client software. VPNs offer a good third-party service for encrypted, secure connections between remote users within a private network.
The other two types of VPN are both site-to-site, meaning that multiple fixed sites are connected over a public network (like the Internet):
2) Intranet (password-protected site for company employees)-based VPN
connects LAN to LAN when a company wants to connect multiple remote connections in one private network.
3) Extranet - based VPN
connects LAN to LAN between multiple companies (such as customers and suppliers) so that they can work in a
shared environment.