Hi,
I'm having a very odd problem, I have my dom U on netbsd, and has worked like clockwork for a little over 3 years now.
Is running xen 3.3 (old I know), I have 12 vms running.
I have a tempalte for CentOS6 and I have 5 of those vms setup with the template, the last time I brought 1 online I forgot to change the mac address of the cfg file and obviusly it took down the one that was live with that mac address.
So A and B end up with the same mac address, so I shutdown B and change the mac address and power it up and also restart A so it could pick up the IP it is assigned (dhcp reservation), also I did delete the leases on both server and client to ensure no issues.
But A is now up, the virtual nic is up, but there is no network connection, nothing.
I check the ARP tables of all doms and erase any reference for A but still nothing.

Any suggestions will be very appreciate.

Cheers.

The problem was Xen related, I changed the VM name in the hyper visor and now is working, I don't know the root cause yet but in case you have the same problem that works.