6.2. Introduction to Networking Modes

Each of the networking adapters can be separately configured to operate in one of the following modes:

  • Not attached. In this mode, Oracle VM VirtualBox reports to the guest that a network card is present, but that there is no connection. This is as if no Ethernet cable was plugged into the card. Using this mode, it is possible to "pull" the virtual Ethernet cable and disrupt the connection, which can be useful to inform a guest operating system that no network connection is available and enforce a reconfiguration.

  • Network Address Translation (NAT). If all you want is to browse the Web, download files, and view email inside the guest, then this default mode should be sufficient for you, and you can skip the rest of this section. Please note that there are certain limitations when using Windows file sharing. See Section 6.3.3, “NAT Limitations”.

  • NAT Network. A NAT network is a type of internal network that allows outbound connections. See Section 6.4, “Network Address Translation Service”.

  • Bridged networking. This is for more advanced networking needs, such as network simulations and running servers in a guest. When enabled, Oracle VM VirtualBox connects to one of your installed network cards and exchanges network packets directly, circumventing your host operating system's network stack.

  • Internal networking. This can be used to create a different kind of software-based network which is visible to selected virtual machines, but not to applications running on the host or to the outside world.

  • Host-only networking. This can be used to create a network containing the host and a set of virtual machines, without the need for the host's physical network interface. Instead, a virtual network interface, similar to a loopback interface, is created on the host, providing connectivity among virtual machines and the host.

  • Generic networking. Rarely used modes which share the same generic network interface, by allowing the user to select a driver which can be included with Oracle VM VirtualBox or be distributed in an extension pack.

    The following sub-modes are available:

    • UDP Tunnel: Used to interconnect virtual machines running on different hosts directly, easily, and transparently, over an existing network infrastructure.

    • VDE (Virtual Distributed Ethernet) networking: Used to connect to a Virtual Distributed Ethernet switch on a Linux or a FreeBSD host. At the moment this option requires compilation of Oracle VM VirtualBox from sources, as the Oracle packages do not include it.

The following table provides an overview of the most important networking modes.

Table 6.1 Overview of Networking Modes

Mode

VM→Host

VM←Host

VM1↔VM2

VM→Net/LAN

VM←Net/LAN

Host-only

+

+

+

Internal

+

Bridged

+

+

+

+

+

NAT

+

Port forward

+

Port forward

NATservice

+

Port forward

+

+

Port forward


The following sections describe the available network modes in more detail.