VPN (Virtual Private network)

Basic Notes about VPN

A VPN is a private network that uses a public network (usually the Internet) to connect remote sites or users together.It works by encapsulating data for one network inside of an ordinary IP packet and transporting that packet to another network. When the packet arrives at the destination network, it is unwrapped and delivered to the appropriate host on the destination network. By encapsulating the data using cryptographic techniques, the data is protected from tampering and snooping while it is transported over the public network.

Through VPN you can access your private network in remote location over Internet without compromising the security. VPNs allow employees to securely access their company's Intranet while travelling outside the office. Similarly, VPNs securely connect different branch offices together via internet without dedicated lease line and its much cheaper than lease lines. VPNs also use strong encryption to provide privacy and strong authentication to guarantee identity, so they are more secure than traditional networks.By using a VPN, businesses ensure security,That means even if the data is hacked while sending through VPN, hacker can't read data as its in encrypted format.

Different VPNs used 

VPNs can be either remote-access (connecting an individual computer to a network) or site-to-site (connecting two networks together). In a corporate setting, remote-access VPNs allow employees to access their company's Intranet from home or while travelling outside the office, and site-to-site VPNs allow employees in different geographically location to share one network.

One interesting thing to note about VPNs is that there are no standards about how to set them up. If you're establishing your own VPN, though, it's up to you to decide which protocols and components to use and to understand how they work together.

Five basic components of VPNs:

VPN Gateways:
A device used to connect an entire network to the VPN
VPN Client Software: 
Software for individual PCs that allow them to connect to the VPN
Authentication Servers: 
Systems such as certificate authorities and RADIUS servers that guarantee the identity of VPN Gateways and Clients
Manage Servers: 
Systems that provide control, monitoring, alerting and reporting on the VPN
Physical Transport: 
Any IP or Internet connection

Advantages of VPN

Security -- The VPN should protect data while it's travelling on the public network. If intruders attempt to capture the data, they should be unable to read or use it.
Reliability -- Employees and remote offices should be able to connect to the VPN with no trouble at any time (unless hours are restricted), and the VPN should provide the same quality of connection for each user even when it is handling its maximum number of simultaneous connections.
Scalability -- As a business grows, it should be able to extend its VPN services to handle that growth without replacing the VPN technology altogether.