[ovs-discuss] Enable tagged VM(guest) to communicate with external network

Ben Pfaff blp at nicira.com
Fri Sep 27 15:35:55 UTC 2013


On Fri, Sep 27, 2013 at 05:02:31PM +0530, Apoorve Mohan wrote:
> I have configured OVS bridge(br0) on eth0 and tagged my VMs(kvm/qemu
> guests) on br0. I did this as i needed two separate vlans. The VM's with
> the same tag are able to access each other and those with different tags
> are isolated from each other as expected. But the problem is after tagging
> the VM's the link between the external network(via eth0) to my VM's have
> broken. None of the VM's(irrespective of the VLAN's on which they are
> present) are able to ping the outside world.

The FAQ says:

Q: I added a pair of VMs on different VLANs, like this:

       ovs-vsctl add-br br0
       ovs-vsctl add-port br0 eth0
       ovs-vsctl add-port br0 tap0 tag=9
       ovs-vsctl add-port br0 tap1 tag=10

    but the VMs can't access each other, the external network, or the
    Internet.

A: It is to be expected that the VMs can't access each other.  VLANs
   are a means to partition a network.  When you configured tap0 and
   tap1 as access ports for different VLANs, you indicated that they
   should be isolated from each other.

   As for the external network and the Internet, it seems likely that
   the machines you are trying to access are not on VLAN 9 (or 10) and
   that the Internet is not available on VLAN 9 (or 10).



More information about the discuss mailing list