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What is a VPN Kill Switch? And how does it work?

By Tibor Moes / September 2022

What is a VPN Kill Switch? And how does it work?

What is a VPN Kill Switch?

People use virtual private networks (VPNs) more than ever before. Due to worldwide government policies that emphasize the monitoring of online activities, users feel as if they have no privacy anymore.

Therefore, using a VPN to hide their browsing habits makes perfect sense. But what happens when the VPN connection suddenly drops and all activities are visible? This is when a VPN kill switch saves the day.

Summary:

 

  • When you surf the web via a VPN, your data is routed through an encrypted VPN tunnel and therefore anonymous. When the VPN connection fails, your internet traffic is unencrypted and exposed.
  • Luckily, a VPN kill switch will disconnect your internet connection when the VPN fails, preventing any data from being leaked.
  • Once the VPN connection returns, the kill switch reactivates the terminated connection so you can resume your browsing activities.

Tip: Protect yourself online. Install antivirus software to protect your devices from malware and use a VPN service to guard your privacy.

How a VPN Kill Switch Works

Understanding VPN kill switches requires knowledge of how VPNs work. A VPN, or virtual private network, is a tool that creates data tunnels between devices and third-party servers. This tunneling process masks the device’s signature and IP address, making it appear as though the device is located at the IP address of the VPN server.

In doing so, VPN tunneling can hide more than the device’s IP address and location. It can also hide other web activities, browsing histories, passcodes, etc. Such information becomes unreadable to prying eyes due to the encryption used to scramble the data.

Losing the connection to the VPN server makes connected devices visible again. For example, dropping your internet connection, even if only for a few seconds, can force your computer, laptop, or smartphone to revert back to its default settings. It means your online activities become traceable through the IP address given by your ISP (internet service provider.)

In many ways, sudden visibility is one of the biggest dangers of trusting a VPN service with the user’s online privacy and anonymity. This is where a VPN kill switch comes in handy.

A VPN kill switch feature reacts to the sudden connection drop and takes measures to ensure the user’s device doesn’t suddenly become visible. It can do it in many ways, but the most common solution is disconnecting the user’s device from the internet when the VPN server connection drops or an IP address change is detected.

Types of VPN Kill Switches

VPN kill switches have two main classifications. Depending on how it works, a VPN kill switch can be either an application-level kill switch or a system-level kill switch.

Application-Level VPN Kill Switch

An application-level VPN kill switch is often the go-to feature for extra security for users who want more control over their apps and internet usage. This VPN kill switch feature is customizable, and enables users to select several apps to terminate if the VPN connection is lost.

For example, a kill switch can prevent the internet browser from reconnecting to the internet if the device drops connectivity or loses its VPN server connection. Users generally select everyday apps, including the following.

  • Email platforms

  • Internet browsers

  • Torrent clients

  • VoIP or video calling apps

The flexibility of an application-level VPN kill switch feature offers more quality of life and doesn’t interfere with other online tasks and activities that may not require a VPN connection. This type of kill switch works exceptionally well when combined with a split tunneling feature. That’s when users decide what apps connect through a VPN connection and which ones use a standard, unencrypted connection with the IP address assigned by the ISP.

System-Level VPN Kill Switch

The system-level VPN kill switch feature is the safest way to prevent unexpected online visibility. Instead of shutting down selected apps, this feature prevents the device from using mobile data or connecting via Wi-Fi or an Ethernet connection.

As long as the VPN remains active, the system-level kill switch blocks all internet connections until it notices the original VPN connection working again. In doing so, this feature immediately stops IP address and location leaks.

VPN Connection Kill Switch Protocols

There are two additional ways to categorize a VPN kill switch based on the kill switch protocol. Users can choose between an active or passive protocol, depending on what features their VPN service providers offer.

Active Kill Switch

The active kill switch protocol is designed to detect network disruptions. If it notices connection issues with the VPN server, it sends the information to the device and proceeds to terminate unsecured connections.

Passive Kill Switch

Although similar in some ways, a passive VPN kill switch operates differently and more efficiently. Passive protocols only monitor the VPN server connection status. After they detect a signal loss, the VPN connection gets automatically shut down to limit data leaks.

Leading Causes for VPN Connection Drops

VPN connection drops still happen, regardless of a VPN’s reliability. Multiple factors can affect the connection uptime.

Firewall Settings

A firewall can block many apps from accessing the internet, including VPN programs. The connection can drop or be impossible to establish if the VPN isn’t whitelisted in the firewall’s settings. Ensuring that the VPN is on the list of firewall exceptions is mandatory.

Antivirus and Spyware Settings

Programs that detect malware and viruses can also limit the functionality of various apps. They do it to protect the system and prevent malware from spreading through a network. Like a firewall, antivirus and spyware programs have blacklisted and whitelisted apps.

If the VPN makes its way onto the blocklist or blacklist – potentially due to an update – the connection to the VPN server can drop and leave the device exposed to sudden visibility.

Weak Connections

Users who rely on Wi-Fi connections may experience more VPN connection drops than those using an Ethernet connection. Cables provide better uptime and stronger signals, whereas Wi-Fi signals can drop for various reasons.

But the Wi-Fi network doesn’t have to become unresponsive for a connection to drop completely. A weak enough signal can still cause problems, because many VPNs already limit the data transfer speed and add latency.

VPN Client Server Problems

A VPN server is as vulnerable as any other type of server. Anything can happen at its physical location and disrupt normal operations. For example, hacks, a weak connection, power outages, dying hardware, a break-in, earthquakes, and everything in between can damage the server and kill the connection. This would cause the device to remain connected to the internet using its ISP-designated IP address and location without a kill switch feature in place.

Congested Network Traffic

Similar to experiencing a weak Wi-Fi signal, congested network traffic can make it difficult to maintain a strong connection to a VPN server.

VPN Protocol Issues

The type of VPN protocol used to establish a connection can make a big difference. Users relying on the User Datagram Protocol, or UDP, often experience more connection drops. The Transmission Control Protocol, or TCP, offers more stability and is more reliable. Of course, there are many more VPN protocols to consider, and each one comes with its own list of pros and cons.

Experimenting with different protocols is ideal for finding the perfect balance of speed, security, and connection uptime. But using the wrong protocol can lead to VPN server connection drops and unexpected visibility.

Router Settings

Changing the router settings can interfere with the functionality of VPN applications. It can happen when users change their login credentials, ports, privacy settings, etc.

Startup Settings

Most VPN programs are customizable, and can be set up to start when booting the device’s operating system. However, just because a VPN app launches at startup doesn’t mean it automatically becomes active.

Resetting the device or logging out and back in from an operating system profile can terminate the VPN server connection. In these situations, the user’s online activities become visible again. It’s especially dangerous if apps like browsers weren’t shut down prior to the restart. They may automatically reconnect to the previous websites, exposing the user.

Uses for VPN Kill Switches

Using a VPN kill switch is always a good idea because it protects against prying eyes. Not all casual users opt to turn on the kill switch because it can interfere with other online activities, especially in the case of system switches.

But some scenarios benefit from extra caution.

Connecting to Public Wi-Fi Networks

Using a public Wi-Fi network can help some users maintain privacy when browsing. However, that privacy comes at the expense of security. Public wireless networks leave unprotected devices vulnerable to hacks and infection with malware.

The most common dangers of public networks include the following.

  • Session hijacking

  • Man in the middle attacks (MitM)

  • Fake hotspots

In session hijacking, hackers monitor browser activities to learn information such as login credentials, passwords, etc. That information can help them hijack email accounts, banking app accounts, and other sensitive online accounts.

MitM attacks revolve around intercepting communications between devices and networks. In these situations, the man in the middle can read the data packets and obtain confidential information. Anything from file transfers to video calls is vulnerable to interceptions and interference if the connections aren’t encrypted.

Fake hotspots are a growing problem. This is when users connect to illegitimate public networks unknowingly. Threat actors may use names like “Free_Mall_Wireless1” or “Airport_WiFI” and other similar network names to trick users into establishing a connection. But those networks are designed to enable monitoring, data interference, and data interception.

Using a VPN can encrypt a device’s connection to a network, making it nearly impossible for someone to monitor or alter the traffic to and from that device. The active kill switch feature is essential because when the VPN server connection drops, encryption drops with it.

Downloading Torrents

Not all torrents are illegal. Despite that, it’s safe to assume that many people engaging in torrenting and other peer-to-peer (P2P) activities download illegal or copyrighted content. It’s no secret that torrent websites are rich in pirated movies, programs, music, video games, and more.

Connecting to a torrenting application without a VPN makes it possible to monitor the user’s activities through their IP address and location. Someone only has to ask the ISP for the account details associated with an IP address and they can find the person using the device to download content.

Using a VPN will show the VPN server’s IP address instead of the real user’s IP address. Thus, people can benefit from encrypted torrenting. As with any other type of app, the actions become visible again if the VPN connection drops and there isn’t a kill switch feature to protect the user’s privacy.

It’s even more dangerous with torrenting and P2P activities because users may leave their devices on while sleeping, away at work, etc. When users are away from their devices, they’re unlikely to terminate the connection when the VPN no longer encrypts it.

Such exposure when torrenting can have severe ramifications. Due to strict copyright laws, users become exposed to legal actions. And depending on the country, this can result in substantial fines.

Sudden visibility when downloading can lead to significant drops in speed. That’s because not all ISPs are lenient regarding torrenting. An ISP that notices a user using torrent apps consistently may implement throttling to limit their speed. In some cases, they might even restrict access to specific P2P websites. A kill switch is necessary to avoid these unfortunate situations that can turn users into targets.

Browsing in Heavily Regulated Countries

Many journalists use VPNs to bypass geographic restrictions and report from foreign countries. Some activists may use VPNs to escape their countries’ firewalls and communicate with others. Usually, it’s difficult to get around systems like the Great Firewall of China without a VPN connection.

VPNs mask users’ identities and prevent tracking by government or censorship agencies. Losing the connection to the VPN server, especially in a heavily regulated country, can leave people vulnerable to legal action.

A kill switch is an essential VPN feature to ensure no real location leaks can happen when the connection drops. For these situations, a passive, system-level VPN kill switch is preferable. It acts faster and initiates a system-wide connectivity block to eliminate the potential of IP address, location, and browsing activity leaks.

Are All VPNs Equipped With Kill Switches?

Although it seems like a VPN kill switch feature is a must-have tool, not all VPNs come with one. And that includes apps from some of the most reputable VPN service providers. Some may choose to offer a kill switch as part of the premium subscription, while others disregard it completely because their customer base doesn’t need the feature.

As privacy becomes even harder to secure, more VPN service providers have started including kill switches as core features of their programs.

Testing a VPN Kill Switch

Not all VPN programs are equally reliable, and neither are their kill switches. Many VPN kill switches can fail when the device’s internet connection drops or they lose signal strength to their virtual private networks.

It’s best to test the kill switch option, even if the VPN software offers military-grade encryption. A loss in connection can expose the user’s real IP address and leave their sensitive data vulnerable.

Testing a VPN is easy due to how VPN kill switches work.

First, it’s important to launch the VPN app and connect to a server. Secondly, the user should start browsing to check the traffic and ensure it benefits from VPN tunneling.

Then, users should activate the VPN’s kill switch. Once the configuration is complete, users can block the VPN in their antivirus or firewall settings and resume their online activities.

If the kill switch works as it should, the user shouldn’t be able to continue browsing. With the VPN kill switch enabled, the internet connection should be either completely blocked or terminated for select applications when the VPN connection suddenly drops.

A test like this doesn’t have to take more than a few minutes. It depends on the VPN software provider’s implementation and the time it takes to connect to a VPN server.

Two Top-Tier VPN Service Providers With Network Lock and VPN Kill Switches

Some providers have a proven track record of stable software and kill switch efficiency. Whether looking for a Windows, Android, iOS, or macOS kill switch, the following providers offer some of the best VPN software.

NordVPN

NordVPN is a VPN provider with a reliable kill switch to combat VPN disconnections or instances of switching VPN servers from revealing a user’s public IP address.

The VPN’s kill switch has system-level and application-level implementation and works on multiple platforms. In addition, the software works with the WireGuard protocol, known for its speed and encryption capabilities.

Users should configure the kill switch based on their operating system and what protocol works best. For example, macOS devices respond best to the IKEv2 tunneling protocol on NordVPN. OpenVPN also works and supports both the internet kill switch and application-specific kill switch feature.

ExpressVPN

This VPN provider offers an interesting kill switch feature called Network Lock. It’s unique in that it’s designed specifically for the split tunneling of their VPN software.

Enabling the Network Lock VPN kill switch enables the ExpressVPN software to kill the internet connection for apps that pass through tunneling. Other apps retain their internet connection and continue to function.

Final Thoughts on VPN Kill Switches

Although not always enabled by default, especially in VPN programs that offer system- and application-level kill switch features, all users should make it a habit of turning this feature on. It’s necessary to ensure maximum encryption and privacy uptime on all devices, from smartphones to routers to smart TVs and computers.

Resources

 

Frequently Asked Questions

How reliable is a VPN kill switch?

A kill switch is only as reliable as the VPN service provider that built the software. It depends on the specific VPN app’s implementation, scenario, and tunneling protocol capabilities.

Can you disable a VPN kill switch?

Few VPN programs come with permanently enabled kill switches due to the inconveniences they can cause if not properly configured. Therefore, users can usually enable and disable the feature.

When does a VPN kill switch activate?

Kill switches initiate a disconnect when VPN connections are no longer working. It can depend on many factors, from weak signal strength to latency to switching VPN servers and everything in between.

Author: Tibor Moes

Author: Tibor Moes

Founder & Chief Editor at SoftwareLab

Tibor is a Dutch engineer and entrepreneur. He has tested security software since 2014.

Over the years, he has tested most leading antivirus software for Windows, Mac, Android, and iOS, as well as many VPN providers.

He uses Norton to protect his devices, CyberGhost for his privacy, and Dashlane for his passwords.

This website is hosted on a Digital Ocean server via Cloudways and is built with DIVI on WordPress.

You can find him on LinkedIn or contact him here.

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