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What Is A VPN?
December 24th 2011 20:22
Encryption of packets requires extensive resources, corporate environments use, dedicate hardware devices to provide power to handle IPSec encryption. Juniper's SSG is one of the widely used security devices in the market.
People who have used a VPN service to access blocked websites in their offices or school campuses, might just know that a VPN is simply a way to anonymously surf the internet. But a VPN has much more to it, infact it has come up as the most secure way to connect with each other on the Internet, no matter where your location is.
VPN stands for Virtual Private Network. It is simply a virtual connection over the Internet between two sites. As we all know that the Internet is a network of networks where millions of nodes are interconnected all talking to each other using different type of circuits. In order to transfer data to another remote workstation through the Internet, you can imagine how many routes the packets have to take before reaching the destination.
Therefore anybody in the intermediate network can sniff the packet and extract all the critical data out of it. Therefore there should be some way of protecting the data. We use the 'https' service for accessing confidential data on the internet, but how about encrypting the data at much lower levels of the OSI layer to allow communication between many nodes just like we do in a local area network.
This is what a VPN does! It basically encrypts the IP packet using the IPSec suite of protocols, which provides a mechanism of authentication and encryption of IP packets on the Network layer of the OSI layer model along with other encryption mechanism on top of it. These mechanism are the Secure Socket Layer (SSL) and Transport Layer Security (TLS) at the Presentation layer; the same mechanism is used for encryption of the Https service.
This full proof security of VPN allows you to connect with different nodes on the Interent just like you do locally, it is infact considered a type of WAN where different offices are now connecting there branches over cheap and high speed DSL connections using VPN. However a dedicated circuit is till established over several of the WAN technologies as they provide what is called as a Service Level Agreement (SLA) to deliver a guaranteed bandwidth and uptime, which is not available with a DSL connection.
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