Sun Microsystems VIRTUALBOX VERSION 3.1.0_BETA2 - Manual (Page 93)

6 Virtual networking
list at the bottom of the page, which contains the physical network interfaces of your
systems. On a typical MacBook, for example, this will allow you to select between
“en1: AirPort” (which is the wireless interface) and “en0: Ethernet”, which represents
the interface with a network cable.
Depending on your host operating system, the following limitations should be kept
in mind:
• On Macintosh hosts, functionality is limited when using AirPort (the Mac’s wire-
less networking) for bridged networking. Currently, VirtualBox supports only
IPv4 over AirPort. For other protocols such as IPv6 and IPX, you must choose a
wired interface.
• On Linux hosts, functionality is limited when using wireless interfaces for
bridged networking. Currently, VirtualBox supports only IPv4 over wireless. For
other protocols such as IPv6 and IPX, you must choose a wired interface.
Also, setting the MTU to less than 1500 bytes on wired interfaces provided by
the sky2 driver on the Marvell Yukon II EC Ultra Ethernet NIC is known to cause
packet losses under certain conditions.
• On Solaris hosts, there is no support for using wireless interfaces. Filtering guest
traffic using IPFilter is also not completely supported due to technical restrictions
of the Solaris networking subsystem. These issues would be addressed in a future
release of OpenSolaris.
With VirtualBox 2.0.4 and above, it is possible to use Crossbow Virtual Network
Interfaces (VNICs) with bridged networking, but with the following caveats:
– A VNIC cannot be shared between multiple guest network interfaces, i.e.
each guest network interface must have its own, exclusive VNIC.
– The VNIC and the guest network interface that uses the VNIC must be as-
signed identical MAC addresses.
6.5 Internal networking
Internal Networking is similar to bridged networking in that the VM can directly com-
municate with the outside world. However, the “outside world” is limited to other VMs
which connect to the same internal network.
Even though technically, everything that can be done using internal networking can
also be done using bridged networking, there are two good reasons why this additional
mode was implemented:
1. Security. In bridged networking mode, all traffic goes through a physical inter-
face of the host system. It is therefore possible to attach a packet sniffer (such
as Wireshark) to the host interface and log all traffic that goes over it. If, for
93