Describe VPN technology (including: importance, benefits, role, impact, components)

Exam: Cisco 640-816 - Interconnecting Cisco Networking Devices Part 2

Virtual Private Network is a technology which creates a secure channel over the internet so that the remote hosts can communicate securely. When I say secure channel then it means that data sent over the internet is encrypted using various encryption algorithms for ex. 3DES, AES etc.

VPN are very important in a business environment where you have multiple offices across the world and you want offices to communicate securely over the internet. In order to connect all offices with each other, you cannot use a dedicated cable connecting two different offices directly. This is not a feasible solution to pass traffic across the two different offices located thousands of miles away from each other. In this case we can use VPN because it creates a tunnel between the two locations and everything that goes across is encrypted and will be difficult to decrypt it. VPN also provides confidentiality, data integrity and data authenticity.

There are many benefits of using VPN. Some of them are:

1. Maximized Security: VPN connection keeps data encrypted, which means the added security and protection of the sensitive information from hackers.
2. Remote Access/Control: VNP allows to access the information remotely, which is especially useful to companies and corporations whose employees need to be able to access the data from home or other places away from the office, like in business trips. So if you are at home and you want to access any file server or any desktop from your home, you can do that through VPN.
3. Online Anonymity: You can hide your ip address when accessing any of the website on internet when connected using VPN. In this case the ip address of the VPN server will be used as a source ip address.
4. Reduce Cost: The maintenance costs of a launched VPN network are extremely low.
5. Prioritize traffic: VPN provide you with an option called Quality of Server (QoS) where you can prioritize any specific traffic across the VPN tunnel.

There are different types of VPN's. They are named on the basis of the role they play in a business.

1. Remote Access: It allows remote users to connect securely to the corporate network wherever and whenever they need to.
2. Site to Site VPN: Site to Site VPN is used when there are multiple hosts need to connect to multiple remote hosts sitting behind a public ip address. For example, company A (192.168.1.0/24) needs to talk to company B (192.168.1.0/24), then we will use site to site VPN because a complete subnet needs to talk to multiple hosts on the remote side.
3. Extranet VPN: This type of VPN allows organization's suppliers, partners and customers to be connected to the corporate network in a limited way for business to business communications.