VirtualBox, if_bridge and bridged networking

[Stefan Bethke]

Am 16.04.2013 um 12:13 schrieb Nicolas de Bari Embriz Garcia Rojas:

> On 04/16/2013 09:31, Stefan Bethke wrote:
>> Hey,
>> 
>> I'm a bit stumped getting a (FreeBSD guest) VM to use bridged networking to work.  The same VM works fine on a Mac OS X and an Ubuntu host, so I'm certain it's not the VMs setting.
>> 
>> I'm running
>> # pkg info -g virtualbox*
>> virtualbox-ose-4.2.6           A general-purpose full virtualizer for x86 hardware
>> virtualbox-ose-kmod-4.2.6_4    VirtualBox kernel module for FreeBSD
>> on FreeBSD 9.1-STABLE r249476 amd64.
>> 
>> My LAN gets to the host via vlan1 (attached to re0); which in turn is bridged via bridge0.  IP configuration is on bridge0.
...
> 
> Try creating a tap interface and later bridge your VM to that  tap.
> 
> in your host create a bridge containing re0 and tap0.

Thanks, that worked!

Since I couldn't find documentation online, here's my working setup for the archives:

My primary LAN comes into the host physically via re0; it's on vlan1.  It is bridged via bridge0 to tap0, where it gets connected to a remote site via OpenVPN.  Relevant bits from rc.conf (addresses changed):

cloned_interfaces="bridge0 tap0 vlan1 vlan2 vlan3 vlan4 gif0"
ifconfig_re0="up"
ifconfig_vlan1="vlandev re0 vlan 1"
ifconfig_bridge0="ether 02:00:00:00:00:01 addm tap0 addm vlan1"
ifconfig_bridge0_alias0="inet 192.0.2.1/26"
ifconfig_tap0="up"

I've extended this config to include tap1, to be used for VirtualBox bridging:
cloned_interfaces="bridge0 tap0 tap1 vlan1 vlan2 vlan3 vlan4 gif0"
ifconfig_bridge0="ether 02:00:00:00:00:01 addm tap0 addm tap1 addm vlan1"
ifconfig_bridge0_alias0="inet 192.0.2.1/26"
ifconfig_re0="up"
ifconfig_vlan1="vlandev re0 vlan 1"
ifconfig_tap0="up"
ifconfig_tap1="up"

Additionally, VirtualBox needs to be able to open the tap interface.  Two settings are necessary: in /etc/sysctl.conf, add:
net.link.tap.user_open=1

In /etc/defvs.rules, under the rule section for your host, add:
add path tap* group wheel mode 660

Then configure the VM to use tap1 for bridging:
VBoxManage modifyvm FreeBSD-9-mini --bridgeadapter1 tap1

That should be it!


Stefan

-- 
Stefan Bethke <stb at lassitu.de>   Fon +49 151 14070811