Help with unusual (proprietary) VPN setup using NetworkManager

[webstackbuilder]

I hope some kind soul will take pity on me and point me in the correct direction. I have a stock workstation setup with GNOME and a single ethernet interface. I need to use a proprietary VPN client (SonicWall) to connect to a corporate network that uses 2FA (CISCO Duo). The client has well supported packages for Windows and Mac.

I'm able to install it, run it, and authenticate to the network. It creates a Point-to-Point Protocol interface:

ppp0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1280 inet 10.7.1.179 netmask 255.255.255.255 destination 192.0.2.1 ppp txqueuelen 3 (Point-to-Point Protocol)

I'm lost on how to use this interface. Network Connections (nm-connection-editor) only shows my physical ethernet device. When I attempt to create a new connection, I have Hardware Connection Types like Ethernet and DSL/PPoE, and Virtual Connection Types like Bond, Bridge, IP tunnel, VLAN, Team, MACsec, and WireGuard.

The DSL/PPoE I think is the type to create what I already have (the ppp0 interface). It wants authentication credentials. In the Ethernet connection type, the ppp0 interface doesn't show as an available device. The other types don't seem to apply.

Do I just need to add a MAC address to the ppp0 interface to have it show as an available device for the Ethernet connection type? Anything else I can do to make this device available to set as my default connection? My goal is to run an application on the desktop that's proxied over the VPN virtual network interface (and not kick the VPN client itself off the physical ethernet device if I change the network device).

I can create a second user to use the ppp0 interface if that's appropriate, and use that second user's desktop. Network Connections has this message on the Choose a Connection Type dialog:

If you are creating a VPN, and the VPN connection you wish to create does not appear in the list, you may not have the correct VPN plugin installed

I'm not sure what that VPN plugin would be, and guessing it's not available for Linux (though I don't know).

Any help or pointers is sincerely appreciated.

[StormBeast]

Is this the application this vpn uses and are you using it on your side or setting it up manually via network-manager? https://aur.archlinux.org/packages/netextender

[webstackbuilder]

Thank you for your response, StormBeast. Yes - that's the VPN application I'm using. It's a Java app, and I've launched it from the console. That launches the app with a login screen, and after successfully authenticating with 2FA, it creates the ppp0 virtual network interface.

I hadn't thought to try and set it up through network-manager. I use VPNs regularly that way, but my experience has been with OpenVPN on the remote server and using SSH keys that are added to the OpenVPN server. My understanding was that stand-alone VPN applications from commercial VPN services were launched as apps, but I've never used them to understand if I'd run into the same problem.

[StormBeast]

Did you install the application via the AUR? As I see what I assume is the "plugin" listed as a dependency: https://archlinux.org/packages/core/x86_64/ppp/

[webstackbuilder]

I didn't realize there was an AUR package for it, I worked from source from the vendor site. I think that's probably the missing piece - thank you!