My apologies, I copied the wrong controller window.... In the capture below, you will see several packets come in from 08:81:f4:a6:dc:01. Eventually, fa:16:3e:a7:ae:63 replies and ICMP requests are redirected to this backup controller. root@overcloud-controller-0 ~]# ip netns exec qrouter-b65e3bdc-390e-48b7-9cd9-fca429dafb45 ip a 1: lo: mtu 65536 qdisc noqueue state UNKNOWN qlen 1 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 28: ha-94c36543-95: mtu 1446 qdisc noqueue state UNKNOWN qlen 1000 link/ether fa:16:3e:52:98:a4 brd ff:ff:ff:ff:ff:ff inet 169.254.192.8/18 brd 169.254.255.255 scope global ha-94c36543-95 valid_lft forever preferred_lft forever inet6 fe80::f816:3eff:fe52:98a4/64 scope link valid_lft forever preferred_lft forever 29: qr-1656d4d1-2c: mtu 1446 qdisc noqueue state UNKNOWN qlen 1000 link/ether fa:16:3e:54:77:0b brd ff:ff:ff:ff:ff:ff 30: qg-3f327e61-8b: mtu 1496 qdisc noqueue state UNKNOWN qlen 1000 link/ether fa:16:3e:a7:ae:63 brd ff:ff:ff:ff:ff:ff [root@overcloud-controller-0 ~]# ip netns exec qrouter-b65e3bdc-390e-48b7-9cd9-fca429dafb45 bash [root@overcloud-controller-0 ~]# tcpdump -nnvv -e -i qg-3f327e61-8b tcpdump: WARNING: qg-3f327e61-8b: no IPv4 address assigned tcpdump: listening on qg-3f327e61-8b, link-type EN10MB (Ethernet), capture size 65535 bytes 15:11:03.232415 08:81:f4:a6:dc:01 > 01:00:5e:00:00:0d, ethertype IPv4 (0x0800), length 68: (tos 0xc0, ttl 1, id 30322, offset 0, flags [none], proto PIM (103), length 54) 10.19.108.254 > 224.0.0.13: PIMv2, length 34 Hello, cksum 0x4fa8 (correct) Hold Time Option (1), length 2, Value: 1m45s 0x0000: 0069 LAN Prune Delay Option (2), length 4, Value: T-bit=1, LAN delay 500ms, Override interval 2000ms 0x0000: 81f4 07d0 DR Priority Option (19), length 4, Value: 1 0x0000: 0000 0001 Generation ID Option (20), length 4, Value: 0x7c75897b 0x0000: 7c75 897b 15:11:17.743272 08:81:f4:a6:dc:01 > 33:33:00:00:00:0d, ethertype IPv6 (0x86dd), length 110: (class 0xc0, hlim 1, next-header PIM (103) payload length: 56) fe80:52:0:136c::fe > ff02::d: PIMv2, length 56 Hello, cksum 0x018f (correct) Hold Time Option (1), length 2, Value: 1m45s 0x0000: 0069 LAN Prune Delay Option (2), length 4, Value: T-bit=1, LAN delay 500ms, Override interval 2000ms 0x0000: 81f4 07d0 DR Priority Option (19), length 4, Value: 1 0x0000: 0000 0001 Address List Option (24), length 18, Value: 2620:52:0:136c::fe 0x0000: 0200 2620 0052 0000 136c 0000 0000 0000 0x0010: 00fe Generation ID Option (20), length 4, Value: 0x00ec032c 0x0000: 00ec 032c 15:11:31.219937 08:81:f4:a6:dc:01 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Ethernet (len 6), IPv4 (len 4), Request who-has 10.19.108.155 tell 10.19.108.254, length 46 15:11:31.646955 08:81:f4:a6:dc:01 > 01:00:5e:00:00:0d, ethertype IPv4 (0x0800), length 68: (tos 0xc0, ttl 1, id 4988, offset 0, flags [none], proto PIM (103), length 54) 10.19.108.254 > 224.0.0.13: PIMv2, length 34 Hello, cksum 0x4fa8 (correct) Hold Time Option (1), length 2, Value: 1m45s 0x0000: 0069 LAN Prune Delay Option (2), length 4, Value: T-bit=1, LAN delay 500ms, Override interval 2000ms 0x0000: 81f4 07d0 DR Priority Option (19), length 4, Value: 1 0x0000: 0000 0001 Generation ID Option (20), length 4, Value: 0x7c75897b 0x0000: 7c75 897b 15:11:43.561269 08:81:f4:a6:dc:01 > 01:00:5e:00:00:0d, ethertype IPv4 (0x0800), length 90: (tos 0xc0, ttl 1, id 16320, offset 0, flags [none], proto PIM (103), length 76) 10.19.108.254 > 224.0.0.13: PIMv2, length 56 Bootstrap, cksum 0xac4c (correct) tag=934a hashmlen=30 BSRprio=100 BSR=10.16.253.254 (group0: 239.255.0.0/16 RPcnt=3 FRPcnt=3 RP0=10.16.253.242,holdtime=2m30s,prio=100 RP1=10.16.253.253,holdtime=2m30s,prio=0 RP2=10.16.253.254,holdtime=2m30s,prio=0) 15:11:46.972690 08:81:f4:a6:dc:01 > 33:33:00:00:00:0d, ethertype IPv6 (0x86dd), length 110: (class 0xc0, hlim 1, next-header PIM (103) payload length: 56) fe80:52:0:136c::fe > ff02::d: PIMv2, length 56 Hello, cksum 0x018f (correct) Hold Time Option (1), length 2, Value: 1m45s 0x0000: 0069 LAN Prune Delay Option (2), length 4, Value: T-bit=1, LAN delay 500ms, Override interval 2000ms 0x0000: 81f4 07d0 DR Priority Option (19), length 4, Value: 1 0x0000: 0000 0001 Address List Option (24), length 18, Value: 2620:52:0:136c::fe 0x0000: 0200 2620 0052 0000 136c 0000 0000 0000 0x0010: 00fe Generation ID Option (20), length 4, Value: 0x00ec032c 0x0000: 00ec 032c 15:12:01.271824 08:81:f4:a6:dc:01 > 01:00:5e:00:00:0d, ethertype IPv4 (0x0800), length 68: (tos 0xc0, ttl 1, id 31628, offset 0, flags [none], proto PIM (103), length 54) 10.19.108.254 > 224.0.0.13: PIMv2, length 34 Hello, cksum 0x4fa8 (correct) Hold Time Option (1), length 2, Value: 1m45s 0x0000: 0069 LAN Prune Delay Option (2), length 4, Value: T-bit=1, LAN delay 500ms, Override interval 2000ms 0x0000: 81f4 07d0 DR Priority Option (19), length 4, Value: 1 0x0000: 0000 0001 Generation ID Option (20), length 4, Value: 0x7c75897b 0x0000: 7c75 897b 15:12:01.797760 08:81:f4:a6:dc:01 > 01:00:5e:00:00:01, ethertype IPv4 (0x0800), length 60: (tos 0xc0, ttl 1, id 32087, offset 0, flags [none], proto IGMP (2), length 32, options (RA)) 10.19.108.254 > 224.0.0.1: igmp query v2 15:12:13.462663 08:81:f4:a6:dc:01 > 33:33:00:00:00:01, ethertype IPv6 (0x86dd), length 86: (hlim 1, next-header Options (0) payload length: 32) fe80:52:0:136c::fe > ff02::1: HBH (rtalert: 0x0000) (padn) [icmp6 sum ok] ICMP6, multicast listener querymax resp delay: 10000 addr: :: 15:12:14.099551 08:81:f4:a6:dc:01 > 33:33:00:00:00:0d, ethertype IPv6 (0x86dd), length 110: (class 0xc0, hlim 1, next-header PIM (103) payload length: 56) fe80:52:0:136c::fe > ff02::d: PIMv2, length 56 Hello, cksum 0x018f (correct) Hold Time Option (1), length 2, Value: 1m45s 0x0000: 0069 LAN Prune Delay Option (2), length 4, Value: T-bit=1, LAN delay 500ms, Override interval 2000ms 0x0000: 81f4 07d0 DR Priority Option (19), length 4, Value: 1 0x0000: 0000 0001 Address List Option (24), length 18, Value: 2620:52:0:136c::fe 0x0000: 0200 2620 0052 0000 136c 0000 0000 0000 0x0010: 00fe Generation ID Option (20), length 4, Value: 0x00ec032c 0x0000: 00ec 032c 15:12:16.982696 4e:14:50:cf:3a:ca > 33:33:ff:cf:3a:ca, ethertype IPv6 (0x86dd), length 86: (hlim 1, next-header Options (0) payload length: 32) fe80::4c14:50ff:fecf:3aca > ff02::1:ffcf:3aca: HBH (rtalert: 0x0000) (padn) [icmp6 sum ok] ICMP6, multicast listener reportmax resp delay: 0 addr: ff02::1:ffcf:3aca 15:12:17.510559 fa:16:3e:a7:ae:63 > 33:33:00:00:00:02, ethertype IPv6 (0x86dd), length 86: (hlim 1, next-header Options (0) payload length: 32) :: > ff02::2: HBH (rtalert: 0x0000) (padn) [icmp6 sum ok] ICMP6, multicast listener reportmax resp delay: 0 addr: ff02::2 15:12:17.615963 08:81:f4:a6:e5:01 > fa:16:3e:a7:ae:63, ethertype IPv4 (0x0800), length 98: (tos 0x0, ttl 59, id 38774, offset 0, flags [DF], proto ICMP (1), length 84) 10.18.81.21 > 10.19.108.161: ICMP echo request, id 4835, seq 18157, length 64 15:12:17.816109 08:81:f4:a6:e5:01 > fa:16:3e:a7:ae:63, ethertype IPv4 (0x0800), length 98: (tos 0x0, ttl 59, id 38860, offset 0, flags [DF], proto ICMP (1), length 84) 10.18.81.21 > 10.19.108.161: ICMP echo request, id 4835, seq 18158, length 64 15:12:18.016286 08:81:f4:a6:e5:01 > fa:16:3e:a7:ae:63, ethertype IPv4 (0x0800), length 98: (tos 0x0, ttl 59, id 38960, offset 0, flags [DF], proto ICMP (1), length 84) 10.18.81.21 > 10.19.108.161: ICMP echo request, id 4835, seq 18159, length 64