can you try using -e with tcpdump to see the ethernet headers - it may be arps from the router to ff:ff:ff:ff:ff:ff that are not getting across in that direction. You should continue tcpdumping on the devices along the path to the instance to see where the arp request (or reply) stops. You do not say which plugin you are using? Is it multinode? (if OVS plugin, GRE or VLANs?) Grizzly? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openstack.org/pipermail/openstack/attachments/20130510/f19a5ea4/attachment.html>