VPN Connection to Fritz!Box fails

Used Networkmanager to create VPN Connection, entered data as provided by Fritz!Box and got the following message:

2014-10-26T08:24:48.645787+01:00 erlangen NetworkManager[733]: <info> Starting VPN service 'vpnc'...
2014-10-26T08:24:48.646472+01:00 erlangen NetworkManager[733]: <info> VPN service 'vpnc' started (org.freedesktop.NetworkManager.vpnc), PID 17580
2014-10-26T08:24:48.654712+01:00 erlangen NetworkManager[733]: <info> VPN service 'vpnc' appeared; activating connections
2014-10-26T08:24:48.663716+01:00 erlangen NetworkManager[733]: <info> VPN plugin state changed: starting (3)
2014-10-26T08:24:48.664567+01:00 erlangen NetworkManager[733]: <info> VPN connection 'Neue VPN-Verbindung' (Connect) reply received.
2014-10-26T08:24:48.721494+01:00 erlangen NetworkManager[733]: <warn> VPN plugin failed: 1
2014-10-26T08:24:48.721879+01:00 erlangen NetworkManager[733]: <info> VPN plugin state changed: stopped (6)
2014-10-26T08:24:48.722201+01:00 erlangen NetworkManager[733]: <info> VPN plugin state change reason: 0
2014-10-26T08:24:48.722655+01:00 erlangen NetworkManager[733]: <info> Policy set 'M-Net' (enp0s25) as default for IPv4 routing and DNS.
2014-10-26T08:24:48.723201+01:00 erlangen NetworkManager[733]: <info> Policy set 'M-Net' (enp0s25) as default for IPv6 routing and DNS.
2014-10-26T08:24:48.723493+01:00 erlangen NetworkManager[733]: <warn> error disconnecting VPN: Could not process the request because no VPN connection was active.
2014-10-26T08:24:53.673344+01:00 erlangen NetworkManager[733]: <info> VPN service 'vpnc' disappeared

my assumption is that you try to connect to another network via vpn. I’m using vpnc for years and hopefully i will be able to help you.
the way is worked for me since day one was to edit this file: /etc/vpnc/default.conf to have the parameters needed by the connection:
IPSec gateway your_server_to_connect_to.com
IPSec server_ID
IPSec secret password_to_connect
XAuth username you.user.name

you start the connection with sudo /usr/sbin/vpnc or as root(be careful what and how you run as root!). Hope it helps!

There are big problems when trying to connect to Fritz!Box:

  • Box is connected to internet via IPv6 and IPv4 Dual Stack Lite, it’s network address being private

  • Desktop I am using to connect to Fritz!Box is connected via IPv4

Can I have a connection between the two?