Isonite wroteI am not using any DNS servers other than the default ones for my ISP
Public DNS servers such as your ISP or google 8.8.8.8 et al have no knowledge of your private LAN machines or your VPN clients, so DNS will not work that way.
Isonite wroteI have tried using "dhcp-option DNS 10.8.0.1"
For that to work you must run your own private DNS server.
You can also consider your OS
hosts file to hold static names.