What VirtualBox Doesn't Tell You

Adapters configured in this way in any virtual machine are attached to a simulated switch on the same virtual network. Unfortunately, a DHCP server is not available in this mode, which means that you have to assign IP addresses manually. Although this is quite easy to set up, the GUI does not give you access to one of VirtualBox's more interesting functions: VirtualBox supports multiple, independent internal networks, which it can run in parallel.

Virtual LANs

To make it easier to identify the virtual LANs, a unique name is assigned to each network. By default, network cards that you set up via the GUI will connect to the internal network called intnet.

VBoxManage

If you need more LANs, there is no alternative to the VBoxManage command-line tool. The tool gives you a full-fledged text-based alternative to the GUI and also offers more in the line of settings. However, its use does entail typing long, cryptic chains of parameters.

To install a second interface (nic2) on a virtual machine called UbuntuVM on an internal LAN called MyNetwork, the modifyvm uses the following command line to modify the settings:

VboxManage modifyvm "UbuntuVM" -nic2 intnet -intnet2 "MyNetwork"

The internal network is like a closed box; without a second interface, the guest is unable to surf the Internet or access the physical LAN.