[libvirt-users] USB network adapter nat support

[Laine Stump]

On 07/10/2018 11:04 AM, Michal Privoznik wrote:
> On 07/10/2018 07:12 AM, Robert Searle wrote:
>> Hi
>>
>> I read wireless nat networks are not supported. What about USB network adapters?  Can I setup a nat network on a USB network adapter?
>>
> 
> I'm not sure what do you mean by "wireless nat network". Isn't the point
> of NAT that it is independent of device that the traffic goes out from?

(just returning from a long time offline, catching up with mailing list
backlog...)

Possibly Robert misunderstood something he read somewhere. libvirt's
virtual networks, and the "nat" forward mode in particular, were created
explicitly to work around the fact that a Linux host bridge can't be
directly attached to a wireless interface. So actually it is "bridged"
connections that don't work with wireless, and NAT is the solution to
this problem.

As for USB - if the USB adapter plugs into a wired network, then the
adapter can be bridged (and guests attached to that same bridge appear
directly on the physical network), but if the USB adapter is a wireless
adapter, then it can't be bridged. In either case, though, you can use
libvirt's "default" network (or create your own virtual network and set
<forward mode='nat'/>) and the guests will be able to make outbound
connections to the physical network, with their IP being NATed to that
of the virtualization host.