How a VPN works — what it does and why it matters

VPNs (virtual private networks) are a popular way to add privacy and change your apparent location online. They route your traffic through a remote server and encrypt the connection between your device and that server, which helps hide your IP address and can prevent local eavesdroppers from seeing your activity.

But VPNs aren’t a silver bullet. They protect the path between you and the VPN server; sites you log into or services you use can still identify you. Performance, trustworthiness and features vary widely between providers, so understanding the basics helps you choose one that fits your needs.

Quick overview — what happens when you use a VPN

• Your VPN client authenticates with a VPN server and they establish an encrypted tunnel (often via TLS).
• All your device’s internet requests are encrypted and sent to the VPN server; that server forwards the requests to their destination.
• Responses return to the VPN server, which encrypts them and sends them back to you to decrypt locally.
• To outside sites, the VPN server’s IP looks like the requester — not your home IP.

Key technical pieces

• Encryption: Symmetric ciphers like AES-256 or ChaCha20 protect the data packets; asymmetric cryptography (TLS handshakes) secures the key exchange that sets up the session.
• Protocols: OpenVPN, WireGuard, IKEv2 and others define how tunnels are built and what encryption suites are used; some providers also use proprietary protocols.
• Tunneling/encapsulation: Traffic is wrapped in an outer packet addressed to the VPN server, which hides the original packet’s metadata from the ISP.

What VPNs are good for — and what they aren’t

• Good for: hiding your IP, securing traffic on public Wi‑Fi, and accessing region‑restricted content.
• Not a panacea: they don’t anonymize content you post while logged in, and you must trust the VPN operator with your traffic.

How to pick a VPN

• Look for clear logging policies, strong encryption, modern protocols (WireGuard or well‑configured OpenVPN), good independent audits, and a jurisdiction that matches your privacy expectations.
• Consider speed tests, simultaneous‑device limits, and extra features (kill switch, split tunneling, leak protection).

Want to dig deeper? Read the original explainer for a fuller technical walk‑through and examples of common protocols: Engadget — How a VPN works. For privacy best practices, Electronic Frontier Foundation is a helpful resource.

Discussion: Do you use a VPN regularly — and what matters most when choosing one: speed, privacy policy, price, or extra features?