Re: Passing multiple ethernet adapters to QEMU guest

[Andrew Wood <andrewjameswood@ymail.com>]

On 14/05/2020 15:50, Reco wrote:
> 	
> Qemu uses /etc/qemu-ifup by default which deliberately puts tap
> interface to the bridge which corresponds to the default route.
Im sorry I dont understand where the default route comes into it as none 
of the interfaces, virtual, bridge or the corresponding real hardware 
interface have any layer 3 addressing assigned, they are purely working 
at L2.

Ive got many VMs working with 1 virtual interface. Some on br1 some on 
br2 some on br3, its only when I try to put a VM on more than one I get 
a problem

The bridges are setup like this

#br1 on enp8s0f1 which has no IP address assigned
/sbin/brctl addbr br1
/sbin/brctl addif br1 enp8s0f1

/usr/bin/tunctl -u root -t br1p0
/sbin/brctl addif br1 br1p0

/usr/bin/tunctl -u root -t br1p1
/sbin/brctl addif br1 br1p1
.
.
.

/sbin/ip link set enp8s0f1 up
/sbin/ip link set br1 up

#br2 on ens7f0 which has no IP address assigned
/sbin/brctl addbr br2
/sbin/brctl addif br2 ens7f0

/usr/bin/tunctl -u root -t br2p0
/sbin/brctl addif br2 br2p0

/usr/bin/tunctl -u root -t br2p1
/sbin/brctl addif br2 br2p1
.
.
.

/sbin/ip link set ens7f0 up
/sbin/ip link set br2 up