I think this is the bug I'm seeing too on Xenial now. Even though I have "Use this connection only for resources on its network" enabled for both IPv4 and IPv6, once the VPN is brought up, all DNS for my LAN (i.e. talking to my internal DNS server) is non-functional and my internal LAN host names are not resolvable.
I think this is the bug I'm seeing too on Xenial now. Even though I have "Use this connection only for resources on its network" enabled for both IPv4 and IPv6, once the VPN is brought up, all DNS for my LAN (i.e. talking to my internal DNS server) is non-functional and my internal LAN host names are not resolvable.