What a VPN does — and what it does not

VPNs are sold with a lot of noise. Here is the plain version.

What it actually does

It encrypts the connection between your device and the VPN server. The network you are sitting on — the café, the hotel, the airport, your broadband provider — can see that you are connected to a VPN, and nothing else. No addresses, no page contents.

It changes the address that websites see. Sites you visit see the VPN server's IP address instead of the one your internet provider gave you. That address is one of the main ways you get tracked and located across the web.

It gets you the internet as it looks somewhere else. Useful when a service is blocked on the network you are using, or when a site behaves differently depending on the country you appear to be in.

What it does not do

It does not make you anonymous. Log into an account and that service knows exactly who you are. Anonymity and privacy are different things — a VPN gives you the second one.

It does not stop malware. If you download and run something harmful, an encrypted tunnel delivers it faithfully.

It does not stop you being scammed. A convincing fake login page works just as well over a VPN. Encryption protects the pipe, not your judgement about who is at the other end.

It does not hide you from a site you are logged into. Your account is the identifier, not your IP.

Where it earns its keep

Public Wi-Fi, where you have no idea who runs the network or who else is on it. Travel, where local networks may be monitored or restricted. Home, where your internet provider can otherwise see every domain you visit and is in some countries permitted to sell that.

The one setting worth checking

Whether your VPN app has a kill switch, and whether it is on. It blocks traffic if the VPN drops, rather than quietly letting your connection fall back to the open network. Without it, a two-second dropout on a train can undo the whole point.