Understanding VPN: Definition, Functionality, and Different Types

VPN stands for Virtual Private Network. 

It allows secured connection channel from a computing device to remote private network or between two private networks using unsecure or public network like the internet. The secure connection is made by using tunneling protocols and encryption that prevent eavesdropping and access to data within the channel. 

Common use of VPN is for emloyees to connect from their computer at home to their company network. This way they can work without dependency of phyisical location and perform secure and private connection to their organization resources. 

Another advantage of using VPN is the ability to browse with the VPN server IP instead of your own public IP. There are services we can use to connect from a server on the other half of the continent and by that obsecure the real physical location. This does not promise full privacy but still useful for some level of anonimity and for bypassing some network restrictions.

Types of VPN 

VPN systems are characterized by lots of features like the tunneling protocol, the number of simultaneous connections, the level of security, the network topology and more  

I’ll  mention division according to the connection type: 

• Remote access – when a computing device connects to an enterprise network. Like an emloyee works from home.
• Site to site – connection between two private networks over a public or unsecure network.
• Intranet-based site-to-site – when the two networks belong to the same organization.
  
• Extranet-based site-to-site – when the two network belongs to different organizations. 

 Security mechanisms 

I mentioned before – VPN use network tunneling protocols and encryption to make the connection secure. 

Let’s dive into some of those protocols: 

• Internet Protocol Security (IPsec) – encrypt and encapsulate an IP packet so the so the information is encrypted in the public Medium and deciphering only at the destination. Works on the network layer. 
• SSL/TLS/DTLS  – establishes secure connection using its uniqe handshake and certificates. Works on the presentetion layer. 
• Microsoft Point-to-Point Encryption (MPPE) – Microsoft point to point encryption protocol.  
• Microsoft Secure Socket Tunneling Protocol (SSTP) – Microsoft point to point tunneling protocol. 
• Multi Path Virtual Private Network (MPVPN) – Microsoft socket tunneling protocol. 
• Secure Shell (SSH) VPN – OpenSSH tunneling protocol to site to site VPN. 
• WireGuard – encrypted and open source communication protocol 
• OpenVPN – VPN system which allows secured connection using certificates and secret keys. orga