Vladimir,

You seem to display a bridge between an 802.3 (eth) and an 802.11 (wnic).

I am running on 4 hours sleep right now and still have 7 hours before I 
may leave for home; thus I apologize for being too exhausted to figure 
out the actual commands and configurations to implement what you display 
that evidently would work.  My laptop has both a physical 802.3 
interface and a physical 802.11 interface, with the 802.3 rarely used 
(most sites only provide 802.11).  Do I add under SL 7.1 a "virtual" eth 
(e.g., an eth1) on the host, then make that a slave to the physical 
802.11 wnic on the host, and then attach VirtualBox to the virtual eth 
on the host via NAT under VirtualBox?

In any event, a copy (typescript, screenshots, etc.) of the actual 
commands you used, any needed configuration files, and a copy of any 
outputs produced during the activation/configuration greatly would be 
appreciated.

As for the comment from someone in this email exchange that VirtualBox 
NAT works from a wnic to the internal 802.3 virtual eth on the virtual 
machine that supports MS Win 7 -- it does not, hence my query.

Yasha Karant

On 10/29/2015 09:11 AM, Vladimir Mosgalin wrote:
> Hi Tom H!
>
>   On 2015.10.29 at 03:24:37 -0400, Tom H wrote next:
>
>> You cannot bridge a wireless NIC:
>>
>> http://www.linuxfoundation.org/collaborate/workgroups/networking/bridge#It_doesn.27t_work_with_my_Wireless_card.21
>>
>> It's been disabled in the kernel's bridging code since 2.6.34 (AFAIR).
> Umm this is on SL7.1 which uses kernel 3.10
>
> $ brctl show
> bridge name     bridge id               STP enabled     interfaces
> bridge0         8000.002590c73bd6       no              eth0
>                                                          wlan0
> $ cat /etc/sl-release
> Scientific Linux release 7.1 (Nitrogen)
>
> I created bridge0 with NM and changed local ethernet to be its slave,
> after that hostapd bridged it with wlan0 with the following config
> interface=wlan0
> bridge=bridge0
>
> The wireless NIC was the random one that I got in package with some
> other motherboard, I didn't mess with firmware or anything like that
>
> $ lspci | grep Wireless
> 01:00.0 Network controller: Qualcomm Atheros AR9462 Wireless Network Adapter (rev 01)
>
> Somehow I doubt that I managed to fall into 1% of users who has special
> card with special firmware. The documents you linked must not be telling
> the whole story. Or just outdated, as it was written in the 2009.
>
>> There are web sites that show how to get around this limitation via
>> either ebtables or proxy-arp. I've never tried either but I assume
>> that, since VirtualBox and VMware allow it, they must use a similar
>> workaround under the cover.
>>
>> I launch VMs with "qemu-system-x86_64 ... -netdev
>> bridge,br=bridge0,id=net0 ..." on my laptop without adding my wireless
>> NIC to br0 and I set up forwarding of a VM's packets with:
>>
>> # echo "1" > /proc/sys/net/ipv4/ip_forward
>> and
>> # iptables -t nat -A POSTROUTING -o wifi0 -j MASQUERADE
>> or
>> # iptables -t nat -A POSTROUTING -s 10.0.2.0/24 ! -d 10.0.2.0/24 -j MASQUERADE
>>
>> If you use libvirt, define a "routed" network with virsh, and choose
>> it when you create a VM, virt-install sets up the forwarding
>> automatically.
>>
>> You haven't said whether you want to be able to access VMs from
>> another box but, FYI, I can ssh to VMs from another laptop by running
>> "ip ro add 10.0.2.0/24 via 192.168.1.43 dev wifi0" on that laptop,
>> where 192.168.1.43 is the ip address of the laptop hosting the VMs.
>>