Re: WLAN and Bridge

On 13.07.25 02:58, Ben Hutton wrote:
> Hi,
>
> Is it possible to use a wlan device with a bridge and tap device for 
> use with bhyve? When I've tried this I cannot seem to get traffic to 
> route past the bridge.

Not really. A normal Ethernet frame has two MAC addresses (source and 
destination).

WiFi adds a third MAC address to each frame (source, destination and 
access point) with the client MAC address authenticated to the access point.

What you want would require a fourth MAC address (source, destination, 
access point, client) to separate the client authentication from 
source/destination MAC address (depending on direction).

Such a frame format exists and is used by WiFi repeaters, but it's not 
commonly supported by FreeBSD WiFi drivers or access points.

> My aim is to get bhyve working with network access on my laptop on 
> WiFi. So far I have had to use Ethernet connections.
All reasonably sane bhyve guest connections look like Ethernet to the 
bhyve guest.
> I have looked into NAT but am unsure how I would do this with bhyve?

You would:

* configure the host as a router

* create a bridge (with a static MAC address if you want to)

* not add any physical interfaces to the bridge

* assign at least on IP address out of an IP prefix assigned to the bridge

* add the bhyve tap interfaces to the bridge

* either configure a firewall (PF, IPFW) to NAT outgoing traffic or 
configure a static route on the next router upstream.

If you control the network including the next router upstream routing 
without NAT is a lot cleaner and easier to understand.

If you want to use it on the go connected to different networks you have 
no alternative but to NAT.

A potential alternative if you're only somewhat in control of the 
network would be to setup proxy ARP/NDP to your one and only WiFi MAC 
address and add host routes, but that would require some tinkering.