What Is a VPN Kill Switch and Why You Need One

A VPN kill switch cuts off your internet if the VPN connection drops. Without it, your device quietly falls back to your normal connection, and your real IP address and traffic are exposed until you notice. With it, nothing gets out until the VPN reconnects.

How it works

The VPN app watches its connection. If the tunnel goes down, because Wi-Fi changes, the server stops responding or the app crashes, the kill switch blocks traffic using your device's firewall. When the VPN reconnects, traffic flows again.

Types of kill switch

• System-wide: blocks all internet traffic when the VPN is down. The safest option.
• App-level: closes or blocks only the apps you choose, such as a torrent client, and leaves the rest online.
• Always-on ("advanced"): blocks traffic whenever the VPN isn't connected, including before it starts after a restart. Some apps call this "block connections without VPN".

Do you need one?

If you use a VPN to hide your IP address, for privacy on public Wi-Fi, for torrenting or in a country with restrictions, yes. VPN connections drop more often than people realize, especially on laptops moving between networks, and a drop without a kill switch defeats the point. If you only use a VPN to watch a show from another region, it matters less.

How to turn it on

• Windows and Mac: look in your VPN app's settings for "Kill switch" or "Network lock". Many apps leave it off by default.
• Android: besides the app's own setting, Android has a built-in option: Settings → Network & internet → VPN → tap the gear next to your VPN → turn on Always-on VPN and Block connections without VPN.
• iPhone: depends on the VPN app; look for a kill switch or "always-on" option in its settings.

How to test it

1. Connect to the VPN and open ipleak.net or a similar test to confirm you're on the VPN's IP.
2. Force a drop: switch Wi-Fi networks, or end the VPN app's process.
3. Try loading a site. With the kill switch working, nothing loads until the VPN reconnects.

Then run a full leak test once you're reconnected. See free VPN leak tests.

Kill switches and browser VPN extensions

Browser VPN extensions usually can't block your whole connection, so they don't have a true kill switch, and if the extension stops, Chrome may go direct. They also don't cover other apps. For the kill switch to protect you, use the provider's desktop app. Chrome can still leak your IP through WebRTC even with the VPN up; WebRTC Privacy Shield closes that gap. See how to prevent IP leaks in Chrome.