Bridging Wifi: Airport To Virtualbox, Easy Steps

Bridging WiFi with VirtualBox can be a tricky process, with many users reporting issues with connecting to the internet. Bridging to a wireless interface is done differently from bridging to a wired interface because most wireless adapters do not support promiscuous mode. This means that all traffic has to use the MAC address of the host's wireless adapter, and VirtualBox needs to replace the source MAC address in the Ethernet header of an outgoing packet to ensure the reply is sent to the host interface.

There are several suggested workarounds for this issue, including using a static IP address, disabling IPv6, and using a wired connection. Some users have also reported success with connecting to WiFi by setting up internet sharing on their Mac and sharing the connection with the VirtualBox VM guests via Thunderbolt Bridge.

Bridged networking not working with wifi on Mac OS X

When attempting to bridge the network connection of a VirtualBox VM to a Wi-Fi interface on the Mac host, users have reported being unable to obtain a DHCP lease or perform any other operations on that interface. This issue specifically occurs when trying to bridge over Wi-Fi, as bridging to an Ethernet interface works without problems.

Several users have suggested potential workarounds for this issue:

• One user reported that they were able to get bridged networking working by turning on Internet sharing on their Mac and sharing their Wi-Fi connection with the VirtualBox VM guests using the Thunderbolt Bridge interface.
• Another user suggested disabling IPv6 on the Wi-Fi interface, as the problem might be related to VirtualBox not working well with IPv6 enabled.
• A third user recommended allowing IP forwarding on the Mac host by using the command "sudo sysctl -w net.inet.ip.forwarding=1".

It is important to note that none of these workarounds are guaranteed to fix the issue, and some users have reported that they did not work for them. Additionally, as of January 2018, a VirtualBox developer commented that if bridged networking with Wi-Fi works, great, but if it doesn't, there is not much that can be done.

Bridged network issue on iMac 2019

A user reported a problem with their 2019 iMac's bridged network connection in August 2019. They were using an Apple AirPort Extreme WiFi adapter to connect to the internet, and had successfully created Windows and Ubuntu VMs on their new iMac with the same configuration as their old iMac. However, they were unable to connect to the internet in either VM, despite trying every possible configuration. The issue seemed to be specific to the newest Apple AirPort Extreme WiFi adapter, as the same setup worked fine on their 5-year-old iMac. The user suspected that the issue needed to be addressed in a VirtualBox update.

Another user suggested that the problem was due to the nature of bridged networking, which is outside the WLAN specification. Bridging to wireless is not true bridging, as the guest shares the MAC of the host, and the host performs a sort of MAC-NAT translation based on IP addresses. This user also noted that promiscuous mode, which is required for bridging, is not part of the official WLAN specifications. Therefore, whether bridging works depends on the combination of routers/access points, WLAN cards, and drivers in use.

A previous issue report from 2014 noted that the problem might be related to IPv6 being enabled, and suggested disabling it as a possible solution. However, another user responded that this was not the case, as the problem persisted even after disabling IPv6.

In response to the 2019 issue report, a user suggested trying to connect with a wired bridged connection or NAT instead of wireless, as these methods were more likely to work.

It is worth noting that, according to the official documentation, bridging virtual network interfaces on a Mac is not possible if the physical network device used for bridging is a wireless device.

Bridged networking on Oracle VM VirtualBox

Bridged networking in Oracle VM VirtualBox allows you to connect a virtual machine to one of your installed network cards and exchange network packets directly, bypassing your host operating system's network stack. This is useful for more advanced networking needs, such as network simulations and running servers in a guest.

To enable bridged networking, open the Settings dialog of a virtual machine, go to the Network page and select 'Bridged Network' in the drop-down list for the 'Attached To' field. Then, select a host interface from the list of physical network interfaces at the bottom of the page. On a typical MacBook, for example, this will allow you to select between 'en1: AirPort' (the wireless interface) and 'en0: Ethernet' (the interface with a network cable).

Bridging to a wireless interface is done differently from bridging to a wired interface because most wireless adapters do not support promiscuous mode. As a result, all traffic has to use the MAC address of the host's wireless adapter, and Oracle VM VirtualBox needs to replace the source MAC address in the Ethernet header of an outgoing packet to ensure the reply will be sent to the host interface. When Oracle VM VirtualBox sees an incoming packet with a destination IP address that belongs to one of the virtual machine adapters, it replaces the destination MAC address in the Ethernet header with the VM adapter's MAC address and passes it on. Oracle VM VirtualBox examines ARP and DHCP packets to learn the IP addresses of virtual machines.

There are some limitations to bridged networking on Oracle VM VirtualBox. On Mac OS X hosts, functionality is limited when using AirPort for bridged networking. Oracle VM VirtualBox only supports IPv4 and IPv6 over AirPort. For other protocols, such as IPX, you must choose a wired interface. Similar limitations apply to Linux hosts.

Troubleshooting bridged networking on VirtualBox

Windows

If you are unable to start VirtualBox VMs configured with a bridged adapter after upgrading your laptop from Windows 7 to Windows 10, try the following:

• Create a VirtualBox Host-Only Ethernet adapter by going to File > Preferences. On the Network tab, select Host-only Networks and click "add a Host-only adapter".
• Go to Network connections on Windows and highlight both the real adapter and the new virtual ethernet adapter that you just created. Right-click and select "Bridge Connections".
• Configure your VM by activating a new adapter and selecting "Attached to Host-only adapter". Choose the VirtualBox Host-Only Ethernet adapter you have just created.
• Configure your static IP Address by modifying /etc/network/interfaces.
• Restart eth0 by running the following commands:

> sudo ifdown eth0

> sudo ifup eth0

Alternatively, you can try the following:

• Open Windows start button and search for "network".
• Choose "View network connections via the control panel".
• Right-click your primary connection and click "Have Disk...".
• Navigate to the associated virtualbox install location for your given drive (e.g. C:\Program Files\Oracle\VirtualBox\drivers\network\netlwf).
• Select the file: VBoxNetLwf.inf in the above directory.
• Select "VirtualBox NDIS6 Bridged Networking Driver".
• Select the bridged adapter in VirtualBox.

If you are still unable to resolve the issue, try uninstalling and reinstalling VirtualBox.

Mac OS X

If you are unable to bridge your Mac OS X AirPort connection, try the following:

Disable IPv6 by running the following commands:

> networksetup -listallnetworkservices (to find the available interfaces)

> networksetup -setv6off Wi-Fi

• Check if the problem is with VirtualBox not requesting an IP address correctly, the DHCP server isn't responding to the IP address request, or a combination of both.
• Manually set the MAC address of the virtual adapter to match the one of your physical card. Go to Settings for the affected virtual machine > Network > Advanced. Set the MAC Address field to your host's adapter one.

Linux

If you are unable to acquire IP addresses on Linux hosts running VirtualBox 6.X, try the following:

• Manually set the MAC address of the virtual adapter to match the one of your physical card. Go to Settings for the affected virtual machine > Network > Advanced. Set the MAC Address field to your host's adapter one.
• Once the virtual machine boots, manually assign a different IP address to your virtual machine.

Bridged networking limitations on Mac OS X, Linux and Oracle Solaris hosts

When using Oracle VM VirtualBox, bridged networking allows you to intercept data from the physical network and inject data into it, creating a new software interface. This enables you to set up routing or bridging between the guest and the rest of your network. However, there are some limitations to bridged networking on Mac OS X, Linux, and Oracle Solaris hosts.

Mac OS X Hosts

On Mac OS X hosts, the functionality of bridged networking is limited when using AirPort, the Mac's wireless networking system. Oracle VM VirtualBox currently only supports IPv4 and IPv6 over AirPort. For other protocols such as IPX, you must use a wired interface. Additionally, there have been reports of issues with bridging over WiFi on Mac OS X, with some users unable to obtain a DHCP lease or connect to the internet.

Linux Hosts

On Linux hosts, bridged networking functionality is also limited when using wireless interfaces. Similar to Mac OS X, Oracle VM VirtualBox on Linux only supports IPv4 and IPv6 over wireless interfaces. For other protocols, such as IPX, a wired interface is required. Furthermore, setting the MTU to less than 1500 bytes on certain wired interfaces can cause packet losses. Some adapters strip VLAN tags in hardware, which can affect VLAN trunking between VMs and the external network.

Oracle Solaris Hosts

Oracle Solaris hosts do not support the use of wireless interfaces with bridged networking. Additionally, filtering guest traffic using IPFilter is not fully supported due to technical restrictions of the Oracle Solaris networking subsystem. There may be issues with certain webcam and isochronous devices, which are known to have poor performance. No ACPI information, such as battery status or power source, is reported to the guest.

Frequently asked questions