Virtual Network Adapter
[VM Guest] ←→ [Virtual Adapter] ←→ [Virtual Switch] ←→ [Physical NIC] ←→ Network
sudo ip addr add 192.168.100.10/24 dev veth0 virtual network adapter
Use Tunnelblick (OpenVPN GUI) which creates utun interfaces automatically. [VM Guest] ←→ [Virtual Adapter] ←→ [Virtual Switch]