> On Thursday, 11 June 2015, 12:00:46, Neil Jerram <neil.jer...@metaswitch.com> > wrote: > > On 11/06/15 10:47, changzhi wrote: >> Hi, all. >> I create a vm and it's neutron port's mac address is >> "fa:16:3e:3f:02:ff". I see "fa:16:3e:3f:02:ff" inside > vm when I run >> "ifconfig eth0". Why does vm's tap device's mac address > is >> "fe:16:3e:3f:02:ff"? Why different between neutron port's mac > address >> and tap device's mac address? Does libvirt create instance tap device >> and its mac address is generated randomly? >> >> Thx >> zhi > > There are two MAC addresses, one at each end of the link between the > host and the VM. > > -------------------+ > Host | +-------------------+ > | | VM | > tap12345-CD ------------------- eth0 | > fa:16:3e:56:71:42 | | fa:16:3e:3f:02:ff | > | | | > | +-------------------+ > -------------------+ > > I believe that both of these addresses are randomly generated, although > I'm not sure exactly which components do that. > > Does that help at all? > > Thanks, > Neil
In neutron.conf you've got base_mac option and "fa:16:3e" is the default value. # Base MAC address. The first 3 octets will remain unchanged. If the # 4h octet is not 00, it will also be used. The others will be # randomly generated. # 3 octet # base_mac = fa:16:3e:00:00:00 # 4 octet # base_mac = fa:16:3e:4f:00:00 Cheers, Radosław Śmigielski __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev