On Mon, Dec 20, 2010 at 11:07 PM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote: > Le mardi 21 dÃcembre 2010 Ã 13:53 +0800, Yueyu Lin a Ãcrit : >> Hello, everyone >> Â Â Â I just encountered a very strange issue in Ubuntu 10.10 server >> edition X86 64bits. ÂI 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 >> Â Â ÂThis 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. >> Â Â Â Are there any restrictions that I Âcan'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. Alex -- 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
