A VPN keeps you safe by encrypting all of your data before it is sent over the internet, masking your IP address to protect your privacy. This means no one is able to see what you are doing online or to track you as long as you are connected to the VPN.
However, sometimes the VPN server you are connected to goes down and you get disconnected. The result: your data is sent over the internet, unencrypted.
A VPN kill switch will prevent this from happening by blocking any connection which is not secured by a VPN.
What If Your VPN Connection Goes Down?
Why might a VPN connection suddenly drop? Maybe the VPN server you’re connected to is experiencing a lot of traffic. Or maybe you get disconnected because your internet connection is unstable.
This doesn’t happen often, but when it does then your data is no longer protected.
In another case, sometimes you might want to switch between two VPN servers. For example, if the server you’re currently connected to is slow, you may choose to connect to a new, faster server. In the few seconds between disconnecting from the old server and connecting to the new server, you could be transmitting data without encryption.
When this happens, your VPN might not be as private as you think it is.
What Is a VPN Kill Switch?
A kill switch protects you in these situations. It is a setting in your VPN client which tells your device to only send data over the internet when you are connected to the VPN.
When your VPN is connected, you can browse the internet as normal. But if your VPN connection goes down, no data will be sent over the internet until you reconnect to the VPN. You won’t be able to load web pages, refresh your email, or send or receive any other data until you reconnect.
A VPN kill switch is also sometimes called a network lock as it locks you out of the network when the VPN isn’t active.
Who Needs a VPN With a Kill Switch?
For most users, the possibility of sending a small amount of unencrypted data over their home network once in a while is not a big deal. But there are some users for whom this could cause a serious problem.
Firstly, people who are avoiding strict government surveillance need to be very careful. If you live somewhere where the government monitors electronic communications then it could be dangerous for you to ever send unencrypted data. Even sending a small amount of unencrypted data could be enough for the government to trace your online activities.
Secondly, journalists may want to use a kill switch to protect their identify. They need to be sure that they are not ever inadvertently revealing any information to people they are in contact with. This is for the protection of both themselves and their confidential sources.
Thirdly, torrent users should always use a VPN with a kill switch. Even though using torrents is not illegal as long as you are not sharing copyrighted content, many ISPs have strict no torrenting rules.
If your VPN goes down while you are using a torrent client then anyone overseeing your network can clearly see you are sending torrent traffic. This could lead to you getting kicked off the network.
The Different Types of VPN Kill Switch
There are different types of kill switch depending on what software you use.
On a desktop, you can have a system-wide kill switch which blocks all traffic when the VPN goes down. Or you can have an app-specific kill switch which blocks traffic only from certain programs. On a mobile app, you will need to enable the kill switch in device settings.
How to Enable the VPN Kill Switch on a Desktop App
VPNs which support a kill switch will have an option to enable it in their desktop clients.
For example, in the ExpressVPN desktop app you can find the Enable Network Lock checkbox in the options menu. Check this and your kill switch will be enabled.
How to Enable an App-Specific VPN Kill Switch
Some VPN clients have an app-specific kill switch. This means you can choose which particular programs on your computer will be barred from sending data if the VPN connection goes down.
This is particularly good for torrent users, as you can add your torrent client to the kill switch list. This will prevent you from sending unencrpyted torrent traffic over your network.
For example, the NordVPN desktop client has an App Kill Switch in the settings menu. Here you can toggle on the kill switch and choose which programs it applies to.
How to Enable the VPN Kill Switch on a Mobile App
When it comes to your smartphone, you need to enable the kill switch via your operating system instead of via the VPN app.
In Android 7 there is a system setting for a VPN kill switch. To enable it, go the the Settings menu, then to Connections. At the bottom of this menu, choose More connection settings. Now choose the VPN option.
This brings up a list of VPN apps installed on your device. Tap the cog icon next to the name of your VPN app. You’ll see a toggle for Always-on VPN. Make sure this toggle is set to on. This turns on the system-wide kill switch on Android.
On iOS, go to the Settings menu and then to General. Now go to VPN and tap the blue i next to the name of your VPN app. Find the Connect On Demand toggle and flip this to on.
Which VPN Providers Have Kill Switches?
Not every VPN provider offers a kill switch feature. So if you want to use a kill switch, you’ll need to check whether this is available before you choose a provider.
Here are some VPN providers that do offer a kill switch:
Using a Kill Switch Makes Your VPN More Secure
If you need to be extra careful about online privacy, then enabling a VPN kill switch will prevent you from inadvertently sending unencrypted data over the internet. You can find kill switches for your whole system, for particular programs, or for your mobile device, depending on your needs.
A kill switch is not available from every VPN provider, so if you want to use one then try one of the providers mentioned above. And to see more recommendations for VPN providers, check out our overview of the best VPN services.