A VPN creates a secure tunnel between your pc or mobile device to the service you want to access. This could be a web site, a torrent site server or a streaming services. To accomplish this all your traffic is relayed servers owned by the VPN service provider.
If there are communication issues with your VPN service provider your traffic will default to the standard unsecured internet connection. If you are using the device you may get visual alters that the service went down and that you are using an insecure connection. In this event, you can stop all your activity and wait till the VPN service is back up.
However, there are situations when you don't have access to a pc but you still use the connection. For example to download torrents. If the VPN connection is lost all the traffic will start flowing through an unsecured connection without you knowing.
A VPN kill switch is a software feature that will disable traffic to the default unsecured internet connection if the VPN goes down.
This is typically implemented by having a background service that constantly monitors the health of the VPN connection. If the connection goes unhealthy all the traffic is stopped. When the VPN connection is healthy again traffic is restored and all your services will gain access to the internet.
This prevents scenarios were you are using the VPN but you have no visual alerts of the health of the VPN connection. Each service provider has a different implementation of the kill switch.
Some VPN providers will implement a kill switch at an application level. Where you specify which applications should be stopped if the VPN connection is unhealthy. In that event, the background service will close the application. This feature gives you more granular control over which applications should be stopped. However, it is less secure as you have to manually choose which applications to stop in the event of the VPN connection going down.
Other VPN providers implement a kill switch at the system level which means that all the applications and the underlying operating system will not be able to use an insecure connection.
Not all VPN services have this feature and more often than not you need to enable the kill switch functionality as it is not enabled by default. You must make sure that the functionality.
There are multiple reasons why the connection to your VPN service becomes unhealthy.
Wifi Connection. You have an unstable wifi connection or your device is switching between multiple wifi hotspots resulting in an unstable connection. It is important that you make sure that the infrastructure you have at home or at your office is stable.
VPN Client will crash. All software have bugs and VPN clients are no exception. Your VPN client might crash and lose connection to the VPN servers.
Anti-virus software might interfere with the VPN software installed on your PC. Some anti-virus software monitor the network traffic going in and out of your PC. It is important to make sure that the Anti-virus is compatible with the VPN service you have installed on your PC.
Unstable VPN servers. The VPN service provider might have some issues at the server-side. In such a scenario the VPN client will not be able to maintain a connection with the server.
High-Security Settings. All VPN service providers have different levels of security. The higher the security the more processing power is required at the client-side and at the server-side. Decreasing the security level might improve your connection stability while still maintaining a good level security
The following is the list of VPN Service Providers that have a kill switch
Make sure you check that this feature is available before you commit to buy a service
In the event that your VPN service provider does not have a kill switch, you can opt for third-party software. The best third party service is
The iOS and Android version are free, while for the Windows and Mac you will need to purchase a one-time license.
Installing a VPN service does not guarantee that you are using a secure connection all the time. An unstable connection can result in your VPN Service to not work properly. It is important to safeguard yourself by buying a VPN service that has a Kill Switch functionality and to make sure that it is enabled and configured properly.