This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-users] can't add vlans successfully

On Tue, Aug 11, 2009 at 5:39 PM, Zhang Li<cindy.zhangli@xxxxxxxxx> wrote:
> yes. br100 can access outside world. Does it means vlan is ok? And the
> domainUs in the same vlan can communicate.

So let me get this straight.
- dom0 can access outside world
- domU and domU can communicate
- domU can't access outside world

If that's so, probably iptables or forwarding issue. Do you have
iptables configured? What is the value of
/proc/sys/net/ipv4/ip_forward ?

>> By "And then assign one IP ADDRESS to it. it can't ping the address of
>> outside internet.", does that mean you put IP address on domU but it
>> can't access anywhere? If yes, do a ping from domU and a tcpdump on
>> br100 and eth0.100, see which packets are missing (does arp receives
>> no reply? or is it only the icmp echo/reply gone missing)
> yes. arp receives no reply. And ICMP echo/reply gone missing.
> I think they can connect each other in the same vlan within the same
> IP subnet .
> if it connect to outside, it should need router. I don't know XEN
> whether can do this.

Bridging mode does not need router on dom0. To be accurate, in
bridging mode domU is just like any other physical host on that same
vlan, so you set it  to use the same router/gateway as any other
physical host.

>> Scenario2: you can do vlans on dom0, create a bridge for each vlans,
>> and tell domU to use the bridge. From domU perspective this is similar
>> with connecting to a switch using an access port.
> I think we are saying the same thing.
> But I am not familar with the bridge of XEN, I don't know whether it
> can implement the trunck link.
> For Scenario2, either domain0 or domainU don't need the 8021Q. am I right?

On scenario2 vlan support is only on dom0. You don't need it on domU.


Xen-users mailing list