How can I create a VPN connection with an arbitrary server using an arbitrary protocol in Windows cmd?
Have you looked into rasdial?
Just incase anyone wanted to do this and finds this in the future, you can use rasdial.exe from command prompt to connect to a VPN network
ie
rasdial "VPN NETWORK NAME" "Username" *it will then prompt for a password, else you can use "username" "password", this is however less secure
http://www.msfn.org/board/topic/113128-connect-to-vpn-from-cmdexe-vista/?p=747265