A VPN kill switch is a safety net. When the VPN tunnel unexpectedly disconnects, the kill switch blocks all internet traffic so your real IP can never leak — even for the few seconds it takes to reconnect.
How a kill switch works
The VPN client watches the tunnel connection. If it detects a drop, it either blocks the network adapter entirely (system-level kill switch) or shuts down specific apps (application-level kill switch).
System-level vs app-level
A system-level kill switch blocks all traffic — safest but disruptive. An app-level kill switch closes only the apps you nominate (e.g. torrent clients), leaving the rest of the internet working.
Who needs a kill switch
Anyone doing anything privacy-sensitive: torrenting, journalism, activism, or simply using public Wi-Fi where your ISP can be identified by a single leaked packet.
How to test yours
Start a download, disable Wi-Fi for a moment, re-enable. If the download pauses instead of failing with unprotected packets, the kill switch is working.
Frequently asked questions
QDo all VPNs have a kill switch?
Most premium ones do; free and cheap VPNs often skip it.
QIs a kill switch on by default?
Usually no — enable it manually after installing.
QDoes a kill switch slow the VPN?
No, it only activates on disconnect.
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