[CentOS-virt] xenbr0 isn't created anymore

Tue Apr 1 18:26:18 UTC 2008
Ross S. W. Walker <rwalker at medallion.com>

Kai Schaetzl wrote:
> Ross S. W. Walker wrote on Tue, 1 Apr 2008 11:14:58 -0400:
> > Yeah, I would use xenbr0 (or eth0 in 3.2 parlance) as the bridge
> > if you plan on using an external DHCP server and avoid the
> > whole NAT and dnsmasq mess. I would probably use virbr0 as a
> > nice virtual network only service, remove forwarding and NAT
> > on it and keep it for internal traffic only.
> virbr0 ist just there when libvirtd gets started, it's useless as it is 
> not bridged to anything anymore. However, I'm not able to reproduce my 
> last results consistently. As expected once I rebooted the problem was 
> back and now I can start libvirtd, kill dnsmasq and still get no IP 
> address. I also found a posting on xen-users that describes exactly my 
> problem and solution
> http://lists.xensource.com/archives/html/xen-users/2007-08/msg
> 00716.html
> and the solution is in that direction I suspected. I tried that and again 
> it doesn't work consistently for me. If I do "iptables -A FORWARD -s 
> -d -j ACCEPT" it seemed to work first, but then stopped 
> working as well. I now get an IP when booting up the VM, but it doesn't 
> last long as the reacknowledgement doesn't travel back.
> So, bridging and networking is fine except for DHCP, damn.

I also read a posting recently on xen-users where the OP wasn't
receiving broadcast arps to the domUs and the solution was to
upgrade to the latest network drivers which fixed the problem.

It was a later kernel then 2.6.18 though, so I don't know if it
applies, but upstream is always backporting from newer kernels,
so who knows. Couldn't hurt (can't believe I said that, cause
now IT WILL!).



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