GLOSSARY
Kill switch
A kill switch is a VPN feature that blocks your internet access whenever the VPN connection drops, so that no traffic is sent over your normal, unprotected connection. It may block everything, or only the apps you choose.
Why it matters
VPN connections fail briefly all the time, when you change Wi-Fi networks, wake a laptop or lose signal. Without a kill switch, your device quietly falls back to the regular connection, and apps carry on exposing your real address and lookups until you notice. For privacy, the gap matters more than the outage.
In practice
Implementations differ. Some apps use firewall rules at the operating system level, others only watch the tunnel and react after it fails. Android offers an Always-on VPN option with a block setting, and many desktop VPN apps include a kill switch toggle. Test it by connecting, switching your Wi-Fi off and on, and then running the IP check.
Related terms
- VPN: A VPN creates an encrypted tunnel between your device and a server operated by the VPN service.
- DNS leak: A DNS leak is when your device sends its DNS lookups to a resolver you did not intend, usually your internet provider's, while you believe a VPN or proxy is handling your traffic.
- Split tunneling: Split tunneling lets you decide which apps, sites or destinations go through the VPN tunnel and which use your normal internet connection.
- IP address: An IP address is a number that identifies a device or network connection on the internet, in the way a street address identifies a building.