What is a VPN, and what does it actually hide?

A VPN (Virtual Private Network) routes your internet traffic through an encrypted tunnel to a server operated by the VPN provider before it reaches its final destination. To websites and networks you connect to, it looks like your traffic is coming from the VPN server's location, not your actual device.

This is genuinely useful for a few specific things: encrypting your traffic on untrusted networks like public Wi-Fi, hiding your IP address and rough location from the sites you visit, and getting around network-level blocks that filter by location or IP. It's not a general-purpose 'become anonymous online' tool — the VPN provider itself can usually still see your traffic, and any site you log into still knows who you are regardless of your IP.

One common way a VPN under-delivers on its promise is a DNS leak: if your device's DNS queries keep going to your regular internet provider's resolver instead of being routed through the VPN tunnel, that provider (and potentially anyone watching that traffic) can still see which sites you're visiting, even though your actual web traffic is encrypted.

A quick way to sanity-check this is to compare which DNS resolvers answer a lookup with your VPN on versus off — if you consistently see your home ISP's resolver responding while connected to a VPN that's supposed to route DNS through itself, that's worth investigating with your VPN provider.