Hi Thomas, You may recall a thread started by Perry from earlier this month with the title "Trying out Neutron Quickstart running into issues with netns (l2 agent and dhcp agent)" where the DHCP and L3 agents were complaining of RNETLINK resource busy type of errors when trying to set the MAC addr. The workaround was to enable ovs_use_veth. I had been stating that this was a required configuration for some time without knowing the correct reason why but Maru explained it to us later on, so everything is great in that respect. However... (there is always a "however", isn't there?) One of our team was *not* having this issue. In fact everything has been working for him for some time and he has never touched that configuration item. It turns out he was getting updates from the RHEL 6.5 composes build. After we discovered the differences, I downloaded the kernel and firmware rpms and installed them to a 6.4 VM and I also could get away without using the ovs_use_veth. We are doing some additional testing to see just how much works with this kind of setup (devstack, tempest, etc.). So far, it seems that whatever is changed between the openstack kernel and the one in the 6.5 composes addresses the issues that ovs_use_veth works around. Hopefully this info is of some use to you! I'm going to copy and preserve the current state of my VM so let me know if there is anything specific you want me to try with this configuration Cheers, Brent