Adaptador somente para host. Ok, esse aqui está muito errado. Você não terá conectividade com um adaptador somente para host :
6.7. Host-only networking
Host-only networking is another networking mode that was added with version 2.2 of VirtualBox. It can be thought of as a hybrid between the bridged and internal networking modes: as with bridged networking, the virtual machines can talk to each other and the host as if they were connected through a physical Ethernet switch. Similarly, as with internal networking however, a physical networking interface need not be present, and the virtual machines cannot talk to the world outside the host since they are not connected to a physical networking interface.
Instead, when host-only networking is used, VirtualBox
É só uma questão de LEITURA DO DOCS.
O modo em ponte funciona apenas sem pequenos truques na rede cabeada. Veja meus comentários aqui: O VirtualBox não consegue transpor o WiFi com o sistema operacional convidado Você terá muitos aspectos para lidar com isso .
tl, dr: Use a interface nat.