My installation of macOS High Sierra doesn't treat VPN connection as separate connection with it's own settings. Namely, VPN connections don't have their separate tab in System Preferences → Network as for instance USB/Wi-Fi connections.
I would like to be able to set some persistent VPN network preferences e.g. DNS server, Router. Currently I have to put desired settings manually after I've connected to VPN and remove them later, as they are meaningless outside VPN.
Is it up to VPN client to create/not create dedicated tab in preferences, or it's macOS's privilege? Can I workaround this by changing VPN client or via some Terminal commands?
I know that usually VPN provider forces necessary settings for connection, but it's not my case alas.