Hello, I am deploying openstack-ansible with octavia and i can see neutron created network for lb-mgmt-net which also created dhcp namespace for that network which is in vlan27 so far everything good so for testing i have created vm and it didn't get IP address so i have started troubleshooting and i found my namespace sending arp request but not getting reply back. [root@ostack-infra-2-2 ~]# ip netns exec qdhcp-2b94d9df-dd49-45b5-a992-63fee27bfa77 ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ns-5604eec1-20@if132: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 link/ether fa:16:3e:c2:b3:4d brd ff:ff:ff:ff:ff:ff link-netnsid 0 inet 172.27.12.3/21 brd 172.27.15.255 scope global ns-5604eec1-20 valid_lft forever preferred_lft forever inet 169.254.169.254/16 brd 169.254.255.255 scope global ns-5604eec1-20 valid_lft forever preferred_lft forever inet6 fe80::f816:3eff:fec2:b34d/64 scope link valid_lft forever preferred_lft forever This is my linuxbridge [root@ostack-infra-2-2 ~]# brctl show brq2b94d9df-dd bridge name bridge id STP enabled interfaces brq2b94d9df-dd 8000.16d25dbea2cc no br-vlan.27 tap5604eec1-20 on same controller node "ostack-infra-2-2" i have br-lbaas network which has same VLAN 27 subnet IP. now when i ping from dhcp-namespace to outside host on same vlan 27, i can see ARP going out and remote host replying back but my reply coming on br-lbaas interface. [root@ostack-infra-2-2 ~]# ip netns exec qdhcp-2b94d9df-dd49-45b5-a992-63fee27bfa77 ping 172.27.8.4 PING 172.27.8.4 (172.27.8.4) 56(84) bytes of data.

From 172.27.12.3 icmp_seq=1 Destination Host Unreachable From 172.27.12.3 icmp_seq=2 Destination Host Unreachable

on other terminal i am running tcpdump on br-lbaas and i am seeing remote host ARP reply coming on that interface but not going to br-vlan.27 which neutron created. [root@ostack-infra-2-2 network-scripts]# tcpdump -i br-lbaas -nn tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on br-lbaas, link-type EN10MB (Ethernet), capture size 262144 bytes 22:41:38.920858 ARP, Reply 172.27.8.4 is-at 32:7c:a1:91:79:7c, length 46 22:41:39.922167 ARP, Reply 172.27.8.4 is-at 32:7c:a1:91:79:7c, length 46 22:41:40.924052 ARP, Reply 172.27.8.4 is-at 32:7c:a1:91:79:7c, length 46 Do you think i can't create two same subnet bridge on same host?