Configure NetworkManager to drop connections when VPN fails

[trueblue]

Hi all,

I am using a VPN proxy service for privacy reasons. I have configured NetworkManager and it's PTPP VPN plug-in successfully.

I would like to configure NetworkManager to drop connections when the VPN fails so that I do not suffer 'privacy leaks' when it happens.

Any ideas on how to do this ?

[trueblue]

Well, I guess there are no configuration options so I think I will catch dbus notifications that signal the VPN failure and then kill my torrent client so that my traffic doesnt get shaped by my ISP.

Here is a (rudimentary but working) piece of python code that does that:

#!/usr/bin/env python

#
# licensed under GNU General Public License version 2
#

import sys
import traceback

import gobject

import dbus
import dbus.decorators
import dbus.mainloop.glib

import os

def catchall_signal_handler(*args, **kwargs):
    print ("Caught signal (in catchall handler) "
           + kwargs['member'])
    if args[0] >= 6: #vpn disconnect (6) or failure (7)
        print ("killing bittorrent client")
        os.system('killall -9 transmission')

if __name__ == '__main__':
    dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)

    bus = dbus.SystemBus()

    #lets make a catchall
    bus.add_signal_receiver(catchall_signal_handler, signal_name='VpnStateChanged', interface_keyword='dbus_interface', member_keyword='member')

    loop = gobject.MainLoop()
    loop.run()

A possible improvement would be to send a dbus signal to close existing internet connections instead of killing only specific apps. I'll do that later when I have some free time

[Seeked]

I have made some modifications so this will drop the internet connection by disabling the network adapter. This is being used on Debian.

Enjoy!

#!/usr/bin/env python

#
# licensed under GNU General Public License version 2
#

import sys
import traceback

import gobject

import dbus
import dbus.decorators
import dbus.mainloop.glib

import os

def catchall_signal_handler(*args, **kwargs):
    print ("Caught signal: "
           + kwargs['member'])
    if args[0] >= 6: #vpn disconnect (6) or failure (7)
        print ("Killing internet connection...")
	#set eth0 to your network adapter
        os.system('ifconfig eth0 down')
	#if you are using python 3 no raw_input() exists so use input()
	raw_input("Press Enter to enable your network adapter...")
	#set eth0 to your network adapter
	os.system('ifconfig eth0 up')
	print ("Your network adapter has been enabled.")	

if __name__ == '__main__':
    dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
    print ("Monitoring your VPN connection...")
    bus = dbus.SystemBus()

    #lets make a catchall
    bus.add_signal_receiver(catchall_signal_handler, signal_name='VpnStateChanged', interface_keyword='dbus_interface', member_keyword='member')
	
    loop = gobject.MainLoop()
    loop.run()

[jonjadot]

Very helpful, being the paranoid freak I am about privacy, I've taken the 2 ideas and put them together. Have it kill all net enabled programs as well as the network interface. Thanks Guys!