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Hi
I have configured a provider flat network with ipv6 subnet in ra mode 
slaac and address mode slaac. However, when i launched a ubuntu trusty 
VM, it couldn't get the ipv6 address but ipv4 only. I am running the 
trunk code BTW. The command used are:

neutron net-create   --provider:network_type=flat 
--provider:physical_network=datacentre --router:external=true provider-net
neutron subnet-create --ip-version=6 --name=ipv6 
--ipv6-address-mode=slaac --ipv6-ra-mode=slaac provider-net 
2001:470:1f0e:cb4::0/64 --allocation-pool 
start=2001:470:1f0e:cb4::20,end=2001:470:1f0e:cb4::fffe --gateway 
2001:470:1f0e:cb4::3
neutron subnet-create --ip-version=4 --name=ipv4 provider-net 
162.3.122.0/24 --allocation-pool start=162.3.122.4,end=162.3.122.253
neutron router-interface-add default-router ipv6
neutron router-interface-add default-router ipv4

The vm is reachable when i configured the ipv6 address calculated by 
neutron manually on the nic.
How can i get the auto configuration to work on the VM?
Thanks!