Re: Certain Mac Address doesn't work in KVM virtual NICs.

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Le lundi 20 dÃcembre 2010 Ã 23:12 -0700, Alex Williamson a Ãcrit :
> 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
> >>       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





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