i use OpenSuse 13.1 and need to a automatic VPN connection, my VPN use from PPTP, and Getway address is our university Domain.
Are you using Network Manager? I’ve seen a couple of similar approaches using scripts to check that a network interface is active and then activate the VPN connection accordingly. If your comfortable working with bash scripts then this may suit your needs. (I manually connect, since I don’t always need my PPTP VPN.)
A script that starts when the DE starts. You’ll need to edit it to suit:
Using a script located in /etc/NetworkManager/dispatcher.d/
This ArchLinux wiki page will probably be enough to get you sorted
Hope this helps.