Is it possible to have applications stop when the VPN connection goes down?

[mlev...@gmail.com]

I came home today and noticed that the Tunnelblick connection was apparently down (the menubar icon was cycling progressively left to right). This means that since whenever it went down, my various applications continued transferring data without the protection of the VPN. Is there some way to have a script triggered or something else to happen when the VPN connection stops working, for mail etc. that run unattended and shouldn't keep going if the VPN isn't active?

[Tunnelblick developer]

A "kill switch" isn't available in Tunnelblick (yet). See https://groups.google.com/d/msg/tunnelblick-discuss/rsr9knpBFsY/HWLyxSXXAAAJ (which has received no responses).

Until there are some things you could do, if you can write scripts. You can include a "reconnecting.sh" script and/or a "post-disconnect.sh" script in a Tunnelblick VPN Configuration, which will be executed in circumstances when the VPN goes down (it depends on "how" down the connection is). The scripts run as "root" and could terminate applications that would be running or do something like turn off Wi-Fi and/or Ethernet.

[Tunnelblick developer]

A "kill switch" is available in Tunnelblick 3.7.5beta04 which you can update to (on the "Preferences" panel: put a check in "Check for updates to beta versions", then click the "Check Now" button) or download from the Tunnelblick Downloads page.

[Tunnelblick developer]

The "kill switch" is more fully documented at Tunnelblick's Kill Switch.