Due to an unfortunate incident involving sleep mode and an overheated backpack I had the “opportunity” to rebuild my laptop. Since this meant reinstalling OpenStack I used this as an excuse to finally move to the ML2 network plugin for Neutron. I was attempting to add an external network using the normal incantation: neutron net-create external – –router:external=true \ –provider:network_type=flat \ –provider:physical_network=physnet1 While this command completed successfully, I was left without any connectivity between br-int and br-ex, despite having in my /etc/neutron/plugins/ml2/ml2_conf.