I know this is a very old thread but I was looking for a solution to the same problem and I came across this before eventually finding the answer and I wanted to just post it here so somebody else in my shoes would have a shorter trek across the internet.
****Note that you probably have to run cmd.exe as an administrator for this to work**
So here we go, open up the prompt (as an adminstrator) and go to your System32 directory. Then run
C:\Windows\System32>cd ras
Now you'll be in the ras directory. Now it's time to create a temporary file with our connection info that we will then append onto the rasphone.pbk file that will allow us to use the rasdial command.
So to create our temp file run:
C:\Windows\System32\ras>copy con temp.txt
Now it will let you type the contents of the file, which should look like this:
[CONNECTION NAME]
MEDIA=rastapi
Port=VPN2-0
Device=WAN Miniport (IKEv2)
DEVICE=vpn
PhoneNumber=vpn.server.address.com
So replace CONNECTION NAME and vpn.server.address.com with the desired connection name and the vpn server address you want.
Make a new line and press Ctrl+Z to finish and save.
Now we will append this onto the rasphone.pbk file that may or may not exist depending on if you already have network connections configured or not. To do this we will run the following command:
C:\Windows\System32\ras>type temp.txt >> rasphone.pbk
This will append the contents of temp.txt to the end of rasphone.pbk, or if rasphone.pbk doesn't exist it will be created. Now we might as well delete our temp file:
C:\Windows\System32\ras>del temp.txt
Now we can connect to our newly configured VPN server with the following command:
C:\Windows\System32\ras>rasdial "CONNECTION NAME" myUsername myPassword
When we want to disconnect we can run:
C:\Windows\System32\ras>rasdial /DISCONNECT
That should cover it! I've included a direct copy and past from the command line of me setting up a connection for and connecting to a canadian vpn server with this method:
Microsoft Windows [Version 6.2.9200]
(c) 2012 Microsoft Corporation. All rights reserved.
C:\Windows\system32>cd ras
C:\Windows\System32\ras>copy con temp.txt
[Canada VPN Connection]
MEDIA=rastapi
Port=VPN2-0
Device=WAN Miniport (IKEv2)
DEVICE=vpn
PhoneNumber=ca.justfreevpn.com
^Z
1 file(s) copied.
C:\Windows\System32\ras>type temp.txt >> rasphone.pbk
C:\Windows\System32\ras>del temp.txt
C:\Windows\System32\ras>rasdial "Canada VPN Connection" justfreevpn 2932
Connecting to Canada VPN Connection...
Verifying username and password...
Connecting to Canada VPN Connection...
Connecting to Canada VPN Connection...
Verifying username and password...
Registering your computer on the network...
Successfully connected to Canada VPN Connection.
Command completed successfully.
C:\Windows\System32\ras>rasdial /DISCONNECT
Command completed successfully.
C:\Windows\System32\ras>
Hope this helps.