I posted this solution in response to another question but figured many who this may help would never see it there.
NOTE: This solution does NOT require elevation of privileges (every step can be done as standard user).
If you are looking for a way to create a VPN connection to your MX for (Windows XP, 7, 8, 10) users who are out of the office and can't bring their systems in for you to work on, you can make a .pbk (phonebook) file that you can send via email with these steps:
* Create a blank text file on your desktop and then rename it to have a ".pbk" extension
* Open the file (you should see a message saying the phonebook is empty prompting you to add an entry)
* Click Ok
* Select "Workplace network"
* Enter the address to your VPN connection and give it a name and click Next
* Enter your login credentials (optional) and click Create
* With your new connection selected, click Properties
* Verify address on General tab then select the Security tab
* Un-check CHAP options at the bottom and select PAP under "Allow these protocols"
* Select L2TP/IPSec for the type of VPN
* Click the Advanced settings button, select the preshared key option and enter your key then click Ok
* Click Ok to close the Properties
* Click Connect to connect to the new connection
* Enter logon credentials if you did not already do so (optionally select to save credentials) and click Connect
Users who use this type of connection will have to remember to connect via the .pbk file and not via their network connections dialog. (I would recommend having them save it to their desktops.)
You will still need to verify settings on the security tab. In the test that I did I had to enter the preshared key again after transferring the file to another system.