What’s App?

How does our “Kill Switch” work? Are you really safe with our app when your computer joins a new WiFi network? And which default setting should you change (scroll down to number 4!)?
Let’s pop the hood on our own app and list our top five features.

For us, safety is always first, so it’s no shocker that all five involve safety:

First of all (1), we have been working long and hard for a tighter integration with the system firewall. This keeps you safe when your computer is sleeping, disconnecting, reconnecting or changing servers.

Secondly, and probably the first thing you expect (2): we replace all DNS calls to your default provider, most likely your ISP, to the Mullvad DNS (a DNS translates names like www.mullvad.net into an IP address). If we didn’t do this, you would be leaking metadata about what you are doing, and when. Note that, even if some other program somehow changes your DNS settings after Mullvad has started, our app will change them back – immediately.

Thirdly, the feature we mentioned at the beginning of this article; a real Kill Switch (3). Implemented as rules in the firewall mean that they run ALL THE time. But what happens if things break down, if our app stops working? Well, in order to prevent any leaks and problems, the kill switch kicks in, and no traffic leaves your device. The rules in place only allow traffic to the selected Mullvad VPN server via our VPN tunnel. No working tunnel – no traffic.

Fourth (4): Traffic can go outside our VPN tunnel ONLY if you are disconnected. However, if you activated the "block when disconnected" setting, no traffic will leave your device (except connection attempts to establish a VPN connection), even if you turn off the app! Change your default settings for constant privacy.

Fifth, and perhaps smoothest (5): If you use the "block when disconnected" setting, you won’t leak any information at all, even if you accidentally quit the app. Make sure to turn on our “auto-connect on startup” feature. This will ensure that your online presence is secure, even before you log in to your computer.

These are our five favourite features, but what about you? Which feature is your favourite? Discuss on our Facebook or Twitter page.

For the universal right to privacy,

Mullvad