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How to create real kill switch on the OS X

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This hack will create PF firewall rules on mac that will only allow in/out traffic to single IP (TG's VPN server in this case).
When disconnect happens, you won't be able to surf, and only pinging that IP works.

1) Open Temrinal and type this

sudo nano /etc/pf.conf
Enter your admin password after that, and PF file will open
2) Scroll to the bottom, and add the following at the bottom
block out on en0 from to any
block out on en3 from to any
pass out quick on en0 from to pass out quick on en3 from to pass out quick on utun0 from any to any
These rules will block traffic on ethernet and on wifi, unless that traffic is going towards (IP of TG's for example) or unless VPN is connected (last line), then traffic is allowed.
Here utun0 is name of our virtual VPN adapter, and en0 and en3 are names of ethernet and wifi.
You can find out those names by running “ifconfig†in terminal.

3) Enable PF, by running in termial: 
sudo pfctl -e
4) Load the rules 
sudo pfctl -f /etc/pf.conf
Now if VPN gets disconnected, you won't have access to internet, not counting the IP address specified before
5) To regain Internet access, disable PF in terminal sudo pfctl -d
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