How To Understand VPN.
To understand how a VPN works, it helps to first understand how your internet connection works without one.
Without a VPN
When you access a website without a VPN, you are being connected to that site through your internet service provider, or ISP. The ISP assigns you a unique IP address that can be used to identify you to the website. Because your ISP is handling and directing all your traffic, it can see which websites you visit. And your activity can be linked to you by that unique IP address.
With a VPN
When you connect to the internet with a VPN, the VPN app on your device (also called a VPN client) establishes a secure connection with a VPN server. Your traffic still passes through your ISP, but your ISP can no longer read it or see its final destination. The websites you visit can no longer see your original IP address, only the IP address of the VPN server, which is shared by many other users and changes regularly.
Proxying
The VPN server acts like a proxy, or stand-in, for your web activity: Instead of your real IP address and location, websites you visit will only see the IP address and location of the VPN server.
This makes you more anonymous on the internet.
Authentication
Establishing a secure connection is a tricky problem solved by clever mathematics in a process called authentication.
Once authenticated, the VPN client and VPN server can be sure they are talking to each other and no one else.
Tunneling
VPNs also protect the connection between client and server with tunneling and encryption.
Tunneling is a process by which each data packet is encapsulated inside another data packet. This makes it harder for third parties to read in transit.
Encryption
Data inside the tunnel is also encrypted in such a way that only the intended recipient can decrypt it. This keeps the contents of your internet traffic completely private. Even your internet service provider won’t see it.
VPN protocols
VPN protocols are the methods by which your device connects to the VPN server. Some protocols are better for speed, some are better for security, and some simply work better under certain network conditions.
Popular VPN protocols in use today include:
OpenVPN
IKEv2
L2TP / IPsec
PPTP*
WireGuard*
SSTP*
