On Wednesday 03 February 2010 17:56:43 J L wrote: > I am having an odd networking issue. It is one of those "it used to > work, and now it doesn't" kind of things. I can't work out what I am > doing differently. > > I have a virtual machine, started with (among other things): > -net nic,macaddr=fa:9e:0b:53:d2:7d,model=rtl8139 -net > tap,script=/images/1/ifup-eth0,downscript=/images/1/ifdown-eth0 > -net nic,macaddr=fa:02:4e:86:ed:ce,model=e1000 -net > tap,script=/images/1/ifup-eth1,downscript=/images/1/ifdown-eth1 This seems to be missing a vlan= option at least for the second pair: > What I actually get: > * VM: eth1, dest MAC of Host's tap1/br0 > * Host: tap1, dest MAC of Host's tap1/br0 > * Host: br1, dest MAC of Host's tap1/br0 > * Host should, but does not route from br0 to br1 > * Host: tap0, dest MAC of ***Host's tap1/br0*** > * Host: br0, dest MAC of ***Host's tap1/br0** > * Host: eth0, no packet > * Server: eth0, no packet > > As you can see, the packet has egressed both tap interfaces! Is this > expected behaviour? What can I do about this? Qemu forwards this packet to everything inside of the same vlan, which is 0 by default. Does it work with this? -net nic,vlan=1,macaddr=fa:9e:0b:53:d2:7d,model=rtl8139 -net tap,vlan=1,script=/images/1/ifup-eth0,downscript=/images/1/ifdown-eth0 -net nic,vlan=2,macaddr=fa:02:4e:86:ed:ce,model=e1000 -net tap,vlan=2,script=/images/1/ifup-eth1,downscript=/images/1/ifdown-eth1 > If I remove tap0 from the bridge, I then get: > * VM: eth1, dest MAC of Host's tap1/br0 > * Host: tap1, dest MAC of Host's tap1/br0 > * Host: br1, dest MAC of Host's tap1/br0 > * Host should, but does not, route from br0 to br1 > * Host: tap0, no packet > * Host: br0, no packet > * Host: eth0, no packet > * Server: eth0, no packet > > This is the other half of my problem: in this case, with effectively > only one tap, the host is not routing between br1 and br0. The packet > just gets silently dropped. Does anyone know what I am doing wrong? Maybe /proc/sys/net/ipv4/ip_forward is disabled? Arnd -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
