Kill switch
A control that blocks all internet traffic if the VPN tunnel drops, rather than letting it fall back to your normal connection.
Glossary
Always-on VPN
An operating-system-level setting that prevents any traffic leaving the device unless the tunnel is up.
Why it matters
It is stronger than an in-app kill switch because it is enforced by the operating system rather than by the VPN application.
What most explanations leave out
Android exposes this natively; on iOS the equivalent requires a configuration profile or supervised device. If you need traffic to never leave unprotected, the OS setting is the one to use, with the app’s own kill switch as a second layer.
Related terms
Split tunnelling
Routing some applications or destinations through the VPN while leaving others on your ordinary connection.
Terms are defined here because they appear in our scoring rubric or in provider reviews, not to fill a glossary.