What is VPN kill switch and why is it needed?

It is safe to browse internet over a VPN due to multiple reasons. Using a VPN is more important over an open network or while you are connected on a public Wi-Fi. VPN keeps all your transactions encrypted, safe and secure.

However, there are possibilities that you might lose network connectivity in the middle of being connected over a VPN. If your network connection drops, you will be out of the VPN and will be again over a public connection provided by your ISP.

This could be dangerous since all your traffic will be exposed and your activities become traceable. While you might assume your connection is secure, it might actually be vulnerable if your VPN connectivity breaks.

As a countermeasure to the connectivity issue, VPNs add on more reliable services by providing a VPN kill switch feature.

What is Kill Switch?

VPNs are reliable in terms of security. However, in an event where there is a sudden breakdown in the network connectivity, a VPN should not expose your traffic over the open internet.

Many top-rated VPN providers implement VPN kill switch mechanism to avoid the mishandling of a VPN traffic in the event of network breakdown.

There are many real scenarios where you can get disconnected from your VPN. A VPN that implements kill switch features cuts your connectivity to the internet completely or partially based on the configuration.

Using a kill switch feature, the internet traffic is automatically stopped when you lose connection with your VPN server. This ensures your privacy is maintained and no one can see your real IP address.

VPN acts as a protection layer for all your traffic and to ensure your traffic remains protected even when you suddenly get disconnected from a VPN, the VPN service provider must offer a kill switch feature.

Reasons for VPN Disconnection:

There are multiple reasons you may be disconnected from a VPN. However, this could pose a security risk in case your VPN does not implement a kill switch feature.

Some of the common reasons to get disconnected from VPN are:

1. Your firewall or router misconfiguration could be one of the reasons you can get disconnected from your VPN server.
2. An issue with the VPN client. Misconfiguration or sudden crashing of the VPN client.
3. Port supporting the VPN is having issues or is getting blocked.
4. The VPN server has trouble and has gone down.
5. ISP interference in the traffic or connectivity issue.
6. Poor network connectivity or weak signal strength of Wi-Fi.
7. Antivirus or other security software blocking the VPN connection.
8. Using UDP instead of TCP can also be one of the reasons for unstable network connections.
9. Auto-updating a security software could result in blocking VPN connectivity.
10. VPN client which has failed update or has issues during an update.
11. OS level blocking issues.
12. A device attacked by malware can also be a reason to get suddenly disconnected from a VPN connection.

Why is VPN Kill Switch Needed?

Not all VPN service providers come with an inbuilt kill switch mechanism. Most free VPN services do not provide this feature.

Also in certain VPNs, this feature may not be activated by default. In such cases, you would need to make changes to the existing configuration. This is one of the reasons you need to ensure a good kill switch feature is implemented in the VPN service you choose.

There are multiple reasons why a VPN kill switch is so important when you are disconnected from your VPN server:

1. In the absence of kill switch, your traffic is not encrypted and is susceptible to all possible network attacks.
2. Puts your privacy at stake.
3. Your IP address becomes visible and traceable.
4. Your ISP can intercept your traffic and throttle.
5. There is no reliability of connection.
6. If you are connected over a public Wi-Fi, you are exposed to several online threats and privacy concerns.
7. If you are accessing geo-restricted content, you may be traceable.

Types of VPN Kill Switch

There are multiple configuration-based kill switch types that are available in most popular VPNs that support the kill switch feature. This lets you choose the best possible configuration based on your requirements.

There are mainly two VPN kill switch types:

1. Application Level Kill Switch: Application-level kill switch will block specific applications and web services from accessing the internet. These are also referred to as App Killers. Most of them allow you to configure the apps that you would wish to get blocked.
   

   If you do not have the flexibility to choose the applications that will stop working, then even your malware software such as antivirus will be blocked from any updates.

   This level of kill switch ensures your most security intensive applications such as webmail, torrents are stopped from accessing the internet till you get connected to VPN again.

2. System-Level Kill Switch: System-level kill switch is a more elaborate locking mechanism where the complete network for a system is made inaccessible. This only has a configuration to turn it On or Off. This will result in a complete disconnection of network activity for the device.

Certain VPN providers also support LAN based kill switch which can block the complete LAN connection when the kill switch is activated.

Kill switch feature is configurable and can also be turned off. Here in most cases, you can log the connection details and also provide instructions to the VPN client to try and reconnect to the VPN server.

Third-party Kill Switch

A kill switch constantly monitors your connection and gets activated in case you suddenly get disconnected from the VPN. The normal internet connection will be restored once the VPN service is resumed.

Certain third-party applications such as VPNNetMon, VPN Watcher also act as a kill switch. On Windows, you can schedule a Task Scheduler that can be activated to close application automatically when you lose connectivity with VPN.

However, most people prefer VPN based kill switch as it has more flexibility and is easy to manage. A VPN kill switch is easy to set up and is part of the VPN installation. Additionally, this makes VPN service more reliable.

Testing VPN Kill Switch

To test if VPN kill switch works as expected:

1. You can connect to the VPN server and browse internet.
2. Disconnect from the VPN server and keep the VPN client open.
3. Try again to browse the internet. If this is not accessible, then the kill switch has been activated.

Based on the type of kill switch you opt for, you can do multiple testing on the connectivity. For a deeper analysis of traffic, you can use a more sophisticated traffic analysis tool such as Wireshark.