A VPN connects a PC, smartphone, or tablet to another computer (called a server) somewhere on the internet. But, i could comunicate to another pc even without a VPN, so what is the purpose of using it ?
A VPN is a tunnel, usually encrypted, that connects two networks together as if they had a direct link between the two networks. Regardless of the number of hops it takes between the two networks, the tunnel looks like a single hop. The packets inside the tunnel are normally encrypted to maintain privacy (a company with two sites, or two companies, connected by a VPN over the public Internet want to keep proprietary information from falling into the wrong hands).
There are many reasons to use a tunnel. There are protocols that simply cannot be transported on the public Internet (multicast, routing protocols, etc.) that networks may need to share among themselves. Because the tunnel makes it look like a direct connection between the separated sites, and because the outer tunnel packets hide the inner packets, you can transport protocols across the Internet that cannot be transported by the Internet itself.
A VPN link mainly serves two purposes:
- transparent routing: the tunnel allows each side to transparently use the other side's addressing scheme (usually: private IP address space connect over public IP address space); since the source addresses may remain original, they can be used for security/trust
- encryption: traffic is completely encrypted; an eavesdropper can merely detect that there's traffic, but he can't get at the data and can't even see who is talking to whom (metadata), regardless of whether end-to-end encryption is used or not
VPN stand for Virtual Private network. It makes secured tunnel through public internet. Generally we don't use VPN in Local area network and if you want to connect with your branch network in separate location, then best and secured solution will be VPN.
A virtual private network extends a private network across a public network, and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network.
There are two major type of VPNs.
- Site to site VPN
- Remote Site vpn
Especially VPN are secured because It transfer encrypted traffic. Based technically you can find many VPNs such as SSL,IPSec, Flex and many more....