How VPNs Work: Routing Traffic Through an Encrypted Tunnel

Every device on the internet needs an IP address to send and receive data, the way every postal address needs a street and number for mail to arrive. Normally, your internet provider assigns that address, and any website you visit can see it, along with a rough sense of your location and which provider you're using. A VPN, short for virtual private network, changes that arrangement by having your device build an encrypted connection to another computer first, called the VPN server, and routing all your traffic through it, so anyone watching from outside sees only a single encrypted stream headed toward that server, not the actual sites and services you're using.

Building the tunnel

When you connect to a VPN, your device and the VPN server first perform a key exchange, agreeing on a shared secret without ever transmitting that secret in a form an eavesdropper could read, using the same public-key cryptography that underlies how encryption secures a banking website. Once that shared secret is established, every packet your device sends gets wrapped, encrypted, and addressed to the VPN server instead of its real destination, a process often described as tunneling because the original packet is fully encapsulated inside a new encrypted one. The VPN server then decrypts the outer layer, forwards your actual request to its real destination, such as a website, waits for the response, and encrypts that response back to send to you. From the website's perspective, the request came from the VPN server's IP address in whatever country that server happens to sit in, not from your own connection.

What this actually hides, and from whom

The most concrete, well-established benefit of a VPN is hiding the contents and destination of your traffic from anyone positioned between your device and the VPN server, which includes your internet service provider and, importantly, anyone else on a shared network like a coffee shop's public Wi-Fi, where an attacker on the same network could otherwise intercept unencrypted traffic. Without a VPN, an internet provider can typically see which domains you visit even if it can't read encrypted page content; with a VPN active, that provider sees only an encrypted connection to the VPN server and nothing about what happens beyond it. This is a real and meaningful privacy improvement in specific situations, particularly on untrusted networks, though it's worth noting that most modern websites already encrypt traffic by default, which independently protects page content even without a VPN.

What a VPN does not hide

A VPN shifts trust rather than eliminating it: your internet provider can no longer see your destinations, but the VPN provider now can, since your traffic is decrypted at their server before being forwarded onward, meaning a VPN's actual privacy value depends heavily on that provider's own logging practices and jurisdiction, something a reputable provider will document in a published policy but that ultimately requires trust rather than direct verification. A VPN also does nothing to stop the destination websites themselves from identifying you through other means once you're there: logging into an account, accepting cookies, or being identified through browser fingerprinting, a technique that profiles a device using detailed characteristics like screen resolution, installed fonts, and browser configuration, all work exactly as well over a VPN connection as without one. Someone who logs into their email through a VPN is just as identifiable to that email provider as someone who doesn't use one at all.

Why streaming services and workplaces block them

Because a VPN changes the apparent location of a connection, streaming services that license content differently by country actively try to detect and block known VPN server IP addresses, leading to a persistent back-and-forth where VPN providers rotate server addresses and streaming services update their blocklists. Corporate VPNs work on a related but distinct principle: rather than hiding a location from the wider internet, they extend a private company network to a remote employee's device, letting that device reach internal tools and file servers as if it were physically plugged into the office network, with access controlled by company-issued credentials rather than by anonymizing anything from the outside world.

Choosing what a VPN is actually for

The realistic case for using a VPN is protecting traffic on networks you don't control, and keeping your general browsing destinations away from your internet provider's view. The unrealistic expectation is that a VPN makes online activity untraceable or grants blanket anonymity, since so much of online identification today happens above the network layer, through accounts, cookies, and fingerprinting, layers a VPN was never designed to touch. Government cybersecurity agencies, including guidance published by the Cybersecurity and Infrastructure Security Agency, generally recommend VPNs specifically for securing traffic on untrusted networks rather than as a general anonymity tool.