Here is the entry in the libvirt wiki describing this problem and the solution:
http://wiki.libvirt.org/page/Virtual_network_%27default%27_has_not_been_started In short, the systemwide dnsmasq instance should have "bind-interfaces" added to its configuration, and the particular interfaces you want it to use should be listed, otherwise dnsmasq will attempt to bind to all existing interfaces at the time it is started, and to any new interfaces that are created after that time. -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to lxc in Ubuntu. https://bugs.launchpad.net/bugs/928524 Title: lxcbr0 fails to come up when dnsmasq is installed To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/dnsmasq/+bug/928524/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs