Thanks a lot. I got the point and I got the exact warning in the virtual machine indeed. Besides the least significant bit should be 0 for the first byte, should I set the second least significant bit to 1 to enforce it as local administrated instead of OUI enforced? On Dec 21, 2010, at 2:19 PM, Eric Dumazet wrote: > Le lundi 20 décembre 2010 à 23:12 -0700, Alex Williamson a écrit : >> On Mon, Dec 20, 2010 at 11:07 PM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote: >>> Le mardi 21 décembre 2010 à 13:53 +0800, Yueyu Lin a écrit : >>>> Hello, everyone >>>> I just encountered a very strange issue in Ubuntu 10.10 server >>>> edition X86 64bits. I just start up my kvm like : >>>> kvm -net nic,macaddr=B3:C0:64:AF:73:28,model=virtio -net >>>> tap,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown,ifname=tap2 >>>> -enable-kvm -drive file=cassandra.raw,format=raw,aio=native -vnc :2 >>>> This Mac address doesn't work at all. No working means the >>>> virtual machine just thinks the eth0 is not plugged in. After I >>>> changed the MAC address, it works as I expected. >>>> Are there any restrictions that I can't use certain MAC >>>> addresses?-- >>> >>> >>> Sure >>> >>> First byte must be even. >>> >>> B3 is odd, so its not valid. >>> >>> low order bit is a marker for 'multicast' >> >> See here for reference: http://en.wikipedia.org/wiki/MAC_address >> >> Typically also makes sense to set the locally administered bit to >> avoid collisions with real devices too. > > KVM should warn the user the given MAC address is wrong. > ifconfig does : > > # ifconfig eth3 hw ether F4:CE:46:87:96:CF > # ifconfig eth3 hw ether F5:CE:46:87:96:CF > SIOCSIFHWADDR: Invalid argument > > > > > -- 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
