[Bridge] Bridge with 1x eth and 2x tun, adding 2nd eth, hosts become unavailable

[Marc Roos]

> > In this situation I can ping a vm from br0 connected to 172.16.1.y
> > 
> > 
> > 
> >                +-----------+           
> >                |    BR0    |           
> >    172.16.1.y  |           |      172.16.1.x
> >        --------|ETH2   TUN1|-------           
> >                |           |           
> >                |           |      172.16.1.x
> >                |       TUN2|-------           
> >                |           |
> >                +-----------+ 
> > 
> > When only adding a 2nd eth adapter with 'brctl addif br0 eth1' 
connected 
> > to 10.11.12.y. The same ping is not working anymore.
> > 
> > 
> >                +-----------+           
> >                |    BR0    |           
> >    172.16.1.y  |           |      172.16.1.x
> >        --------|ETH2   TUN1|-------           
> >                |           |           
> >                |           |      172.16.1.x
> >     10.11.12.y |       TUN2|-------           
> >        --------|ETH1       |
> >                +-----------+           
> > 			             
> > When I remove the eth1 again, the ping starts working again.
> > 
> > Can someone explain me why the bridge is behaving like this? And how 

> > this can be fixed?
> > 
> > 	
> > 
> > 	   
> 
> Are you creating a spanning tree loop?  Also. Bridge is a Layer 2 
device
> not a Layer 3 device; therefore generally all interfaces in a bridge 
have same
> subnet.
> 
I don’t think I am creating a loop, I have stp on and ebtables: 
-i eth2 -o eth1 -j DROP , pcnt = 301 -- bcnt = 17100
-i eth1 -o eth2 -j DROP , pcnt = 3787 -- bcnt = 180148

I would like to achieve that what ever hosts and networks I connect on 
ethx on tunx, could see the other ones located on the the other ethx or 
tunx. Is this not possible with the bridge? Is there another technique 
to do this?