I tried to reproduce but couldn't, i did on master devstack env:- openstack security group create basic openstack security group rule create basic --protocol tcp --dst-port 22:22 --remote-ip 0.0.0.0/0 openstack security group rule create basic --protocol tcp --dst-port 22:22 --ethertype ipv6 openstack security group rule create --protocol icmp basic openstack security group rule create --protocol icmp basic --ethertype ipv6 openstack security group rule create --protocol udp --dst-port 53:53 basic test -f ~/.ssh/id_rsa.pub || ssh-keygen -t rsa -N "" -f ~/.ssh/id_rsa openstack keypair create --public-key ~/.ssh/id_rsa.pub default # nova flavor openstack flavor create --ram 512 --disk 1 --vcpu 1 --public tiny openstack network create ipv6-pd openstack subnet create --ip-version 6 --ipv6-ra-mode slaac --ipv6-address-mode slaac --network ipv6-pd --gateway 2001:db8:2222:d1c::1 --allocation-pool=start=2001:db8:2222:d1c::2,end=2001:db8:2222:d1c:ffff:ffff:ffff:ffff ipv6-pd-1 --subnet-range 2001:db8:2222:d1c::/64 openstack router add subnet router1 ipv6-pd-1 openstack server create --nic net-id=ipv6-pd --image cirros-0.5.2-x86_64-disk --security-group basic --key-name default --flavor tiny testvm $ openstack port list --network ipv6-pd /usr/lib/python3/dist-packages/secretstorage/dhcrypto.py:15: CryptographyDeprecationWarning: int_from_bytes is deprecated, use int.from_bytes instead from cryptography.utils import int_from_bytes /usr/lib/python3/dist-packages/secretstorage/util.py:19: CryptographyDeprecationWarning: int_from_bytes is deprecated, use int.from_bytes instead from cryptography.utils import int_from_bytes +--------------------------------------+------+-------------------+-----------------------------------------------------------------------------------------------------+--------+ | ID | Name | MAC Address | Fixed IP Addresses | Status | +--------------------------------------+------+-------------------+-----------------------------------------------------------------------------------------------------+--------+ | 4e0179bb-1dbd-46bb-b86e-935224889858 | | fa:16:3e:7b:2b:b6 | ip_address='2001:db8:2222:d1c::1', subnet_id='db9e25b3-9a51-488a-b257-658351e928c6' | ACTIVE | | dc7ef71d-ec1d-44eb-be9f-fb2c67f6cac2 | | fa:16:3e:51:0b:fa | ip_address='2001:db8:2222:d1c:f816:3eff:fe51:bfa', subnet_id='db9e25b3-9a51-488a-b257-658351e928c6' | ACTIVE | | f7de9144-45c4-4664-bf91-eb4048de1670 | | fa:16:3e:bd:06:e0 | ip_address='2001:db8:2222:d1c:f816:3eff:febd:6e0', subnet_id='db9e25b3-9a51-488a-b257-658351e928c6' | DOWN | +--------------------------------------+------+-------------------+-----------------------------------------------------------------------------------------------------+--------+ From vm:- $ ping 2001:db8:2222:d1c::1 PING 2001:db8:2222:d1c::1 (2001:db8:2222:d1c::1): 56 data bytes 64 bytes from 2001:db8:2222:d1c::1: seq=0 ttl=254 time=2.191 ms 64 bytes from 2001:db8:2222:d1c::1: seq=1 ttl=254 time=0.785 ms 64 bytes from 2001:db8:2222:d1c::1: seq=2 ttl=254 time=0.834 ms ^C --- 2001:db8:2222:d1c::1 ping statistics --- 3 packets transmitted, 3 packets received, 0% packet loss round-trip min/avg/max = 0.785/1.270/2.191 ms $ sudo ovn-trace ipv6-pd 'inport == "dc7ef71d-ec1d-44eb-be9f-fb2c67f6cac2" && eth.src == fa:16:3e:51:0b:fa && eth.dst == fa:16:3e:65:02:e9 && ip6.src == 2001:db8:2222:d1c:f816:3eff:fe51:bfa && ip6.dst == 2001:db8:2222:d1c::1' # ipv6,reg14=0x3,vlan_tci=0x0000,dl_src=fa:16:3e:51:0b:fa,dl_dst=fa:16:3e:65:02:e9,ipv6_src=2001:db8:2222:d1c:f816:3eff:fe51:bfa,ipv6_dst=2001:db8 :2222:d1c::1,ipv6_label=0x00000,nw_proto=0,nw_tos=0,nw_ecn=0,nw_ttl=0 ingress(dp="ipv6-pd", inport="dc7ef7") -------------------------------------- 0. ls_in_port_sec_l2 (northd.c:5205): inport == "dc7ef7" && eth.src == {fa:16:3e:51:0b:fa}, priority 50, uuid af10c8f9 next; 1. ls_in_port_sec_ip (northd.c:4868): inport == "dc7ef7" && eth.src == fa:16:3e:51:0b:fa && ip6.src == {fe80::f816:3eff:fe51:bfa, 2001:db8:2222:d 1c:f816:3eff:fe51:bfa}, priority 90, uuid 956e95d5 next; 5. ls_in_pre_acl (northd.c:5463): ip, priority 100, uuid 7f9b5be9 reg0[0] = 1; next; 7. ls_in_pre_stateful (northd.c:5669): reg0[0] == 1, priority 100, uuid 2fdb9eda ct_next; ct_next(ct_state=est|trk /* default (use --ct to customize) */) --------------------------------------------------------------- 8. ls_in_acl_hint (northd.c:5748): !ct.new && ct.est && !ct.rpl && ct_label.blocked == 0, priority 4, uuid 5b28b009 reg0[8] = 1; reg0[10] = 1; next; 9. ls_in_acl (northd.c:5974): reg0[8] == 1 && (inport == @pg_32cb109b_1eda_4a3b_b3e5_2269b388b6f1 && ip6), priority 2002, uuid d03ea4c0 next; 22. ls_in_l2_lkup (northd.c:8034): eth.dst == fa:16:3e:65:02:e9, priority 50, uuid 89615973 outport = "536736"; output; egress(dp="ipv6-pd", inport="dc7ef7", outport="536736") [265/1998]------------------------------------------------------- 0. ls_out_pre_lb (northd.c:5355): ip && outport == "536736", priority 110, uuid c0d52ba8 next; 1. ls_out_pre_acl (northd.c:5355): ip && outport == "536736", priority 110, uuid 88fed770 next; 3. ls_out_acl_hint (northd.c:5748): !ct.new && ct.est && !ct.rpl && ct_label.blocked == 0, priority 4, uuid ea31d707 reg0[8] = 1; reg0[10] = 1; next; 9. ls_out_port_sec_l2 (northd.c:5302): outport == "536736", priority 50, uuid f81bc41d output; /* output to "536736", type "patch" */ ingress(dp="router1", inport="lrp-536736") ------------------------------------------ 0. lr_in_admission (northd.c:10271): eth.dst == fa:16:3e:65:02:e9 && inport == "lrp-536736", priority 50, uuid 6d7cecd6 xreg0[0..47] = fa:16:3e:65:02:e9; next; 1. lr_in_lookup_neighbor (northd.c:10352): 1, priority 0, uuid 6438693f reg9[2] = 1; next; 2. lr_in_learn_neighbor (northd.c:10361): reg9[2] == 1 || reg9[3] == 0, priority 100, uuid 4004d6b9 next; 3. lr_in_ip_input (northd.c:10048): ip6.dst == {2001:db8:2222:d1c::1, fe80::f816:3eff:fe65:2e9}, priority 60, uuid 4a85be6b drop; Can you confirm if the above tests are correct, or need to try some other operations to reproduce the issue?