What is a VPN kill switch?
A kill switch is the seatbelt of a VPN: you rarely notice it, but the one moment the connection drops, it stops your apps from quietly falling back to your normal network.
What a kill switch actually does
VPN connections drop more often than people expect — when you switch Wi-Fi networks, your laptop wakes from sleep, or a server hiccups. Without a kill switch, your apps notice the tunnel is gone and simply reconnect over your normal network. For a few seconds your real IP address and traffic are exposed. A kill switch closes that gap by blocking all traffic until the VPN is back.
When it matters most
- On laptops that move between home, office, hotel, and café Wi-Fi.
- During long downloads or uploads where you might not notice a disconnect.
- On restrictive networks where the VPN reconnects often.
- Any time you care more about privacy than a momentary interruption.
How to test your kill switch
- Turn it on
Enable the kill switch in your VPN app’s settings.
- Start something live
Begin a download or open a page that updates continuously.
- Force a drop
Disconnect Wi-Fi for a moment, or switch VPN servers.
- Watch the traffic
It should pause until the VPN reconnects — not carry on over your normal connection.
Good defaults
- Leave it on for desktop and laptop use.
- On mobile, choose the strictest “block connections without VPN” option your provider offers.
- If your app separates system-wide and app-level kill switches, pick system-wide unless you have a clear reason not to.
Frequently asked questions
Should I always keep the kill switch on?
For most people on a laptop or desktop, yes. The small inconvenience of a blocked connection during a reconnect is usually much better than leaking traffic without noticing.
Does a kill switch slow down my VPN?
No. It only acts when the VPN connection drops; it has no effect on your speed while you are connected.
Why did my internet stop when the VPN disconnected?
That is the kill switch doing its job — it blocked traffic to protect you. Reconnect the VPN, or turn the kill switch off if you intentionally want to browse without it.