Desktop Virtualization Network Modes

Both VMWare workstation and Sun VirtualBox have several modes for guest operating systems to use networks. The names below are in the format VMWare terminology/Sun terminology - explanation

• Host only/Network adapter mode - a virtual network adapter is created on the host and used by the guest that is only accessible on the host. Inbound access to the guest is only possible through a proxy server run on the host.
• Network Address Translation (NAT) mode - a virtual network adapter is created on the host and used by the guest; traffic from outside the host can reach the guest via mapping of ports on the host to the guest (handled by the virtualization software). Outbound traffic is unaffected.
• Bridged/Internal mode - a virtual network adapter is created on the host and used by the guest; the adapter works just as if another physical network card were present in the host machine and devoted to the guest OS.

Some diagrams are available here.