Sorry missed ingress rules:
(neutron-openvswitch-agent)[root@uk-dc-tx2-01 /]# iptables -S | grep neutron-openvswi-iba5cd56c-4
-N neutron-openvswi-iba5cd56c-4
-A neutron-openvswi-iba5cd56c-4 -m state --state RELATED,ESTABLISHED -m comment --comment "Direct packets associated with a known session to the RETURN chain." -j RETURN
-A neutron-openvswi-iba5cd56c-4 -d 192.168.200.6/32 -p udp -m udp --sport 67 --dport 68 -j RETURN
-A neutron-openvswi-iba5cd56c-4 -d 255.255.255.255/32 -p udp -m udp --sport 67 --dport 68 -j RETURN
-A neutron-openvswi-iba5cd56c-4 -p tcp -m tcp -m multiport --dports 1:65535 -j RETURN
-A neutron-openvswi-iba5cd56c-4 -p icmp -j RETURN
-A neutron-openvswi-iba5cd56c-4 -p tcp -m tcp --dport 22 -j RETURN
-A neutron-openvswi-iba5cd56c-4 -m set --match-set NIPv40cd3823f-af20-4015-b9f4- src -j RETURN
-A neutron-openvswi-iba5cd56c-4 -m state --state INVALID -m comment --comment "Drop packets that appear related to an existing connection (e.g. TCP ACK/FIN) but do not have an entry in conntrack." -j DROP
-A neutron-openvswi-iba5cd56c-4 -m comment --comment "Send unmatched traffic to the fallback chain." -j neutron-openvswi-sg-fallback
-A neutron-openvswi-sg-chain -m physdev --physdev-out tapba5cd56c-46 --physdev-is-bridged -m comment --comment "Jump to the VM specific chain." -j neutron-openvswi-iba5cd56c-4

And ml2_conf.ini:
[ml2]
type_drivers = flat,vlan,vxlan
tenant_network_types = vxlan
mechanism_drivers = openvswitch,l2population
extension_drivers = port_security

[ml2_type_vlan]
network_vlan_ranges =

[ml2_type_flat]
flat_networks = physnet1

[ml2_type_vxlan]
vni_ranges = 1:1000
vxlan_group = 239.1.1.1

[securitygroup]
firewall_driver = neutron.agent.linux.iptables_firewall.OVSHybridIptablesFirewallDriver

[agent]
tunnel_types = vxlan
l2_population = true
arp_responder = true

[ovs]
datapath_type = system
ovsdb_connection = tcp:127.0.0.1:6640
local_ip = 10.22.20.4


On Tue, Oct 15, 2019 at 4:16 PM Shuai Zhao <kevinzs2048@gmail.com> wrote:
Hi Neutron,
I've deployed Rocky-rc2 version on Debian Buster(compute node), kernel Linux 4.19

Now the issue:
The VM running on the Host(Debian Buster) could not get IP when Booting. I use tcpdump to get the packet on tap, qbr, qvb and qvo. 
The DHCP broadcast packet could be dumped at tap and qbr, but not at qvo/qvb. So the DHCP failed. All the firewall policy is neutron automatic generated.

The firewall policy is never changed.
(neutron-openvswitch-agent)[root@** /]# iptables -S | grep tapba5cd56c-46
-A neutron-openvswi-FORWARD -m physdev --physdev-out tapba5cd56c-46 --physdev-is-bridged -m comment --comment "Direct traffic from the VM interface to the security group chain." -j neutron-openvswi-sg-chain
-A neutron-openvswi-FORWARD -m physdev --physdev-in tapba5cd56c-46 --physdev-is-bridged -m comment --comment "Direct traffic from the VM interface to the security group chain." -j neutron-openvswi-sg-chain
-A neutron-openvswi-INPUT -m physdev --physdev-in tapba5cd56c-46 --physdev-is-bridged -m comment --comment "Direct incoming traffic from VM to the security group chain." -j neutron-openvswi-oba5cd56c-4
-A neutron-openvswi-sg-chain -m physdev --physdev-out tapba5cd56c-46 --physdev-is-bridged -m comment --comment "Jump to the VM specific chain." -j neutron-openvswi-iba5cd56c-4
-A neutron-openvswi-sg-chain -m physdev --physdev-in tapba5cd56c-46 --physdev-is-bridged -m comment --comment "Jump to the VM specific chain." -j neutron-openvswi-oba5cd56c-4

(neutron-openvswitch-agent)[root@*** /]# iptables -S | grep neutron-openvswi-oba5cd56c-4
-N neutron-openvswi-oba5cd56c-4
-A neutron-openvswi-INPUT -m physdev --physdev-in tapba5cd56c-46 --physdev-is-bridged -m comment --comment "Direct incoming traffic from VM to the security group chain." -j neutron-openvswi-oba5cd56c-4
-A neutron-openvswi-oba5cd56c-4 -s 0.0.0.0/32 -d 255.255.255.255/32 -p udp -m udp --sport 68 --dport 67 -m comment --comment "Allow DHCP client traffic." -j RETURN
-A neutron-openvswi-oba5cd56c-4 -j neutron-openvswi-sba5cd56c-4
-A neutron-openvswi-oba5cd56c-4 -p udp -m udp --sport 68 --dport 67 -m comment --comment "Allow DHCP client traffic." -j RETURN
-A neutron-openvswi-oba5cd56c-4 -p udp -m udp --sport 67 --dport 68 -m comment --comment "Prevent DHCP Spoofing by VM." -j DROP
-A neutron-openvswi-oba5cd56c-4 -m state --state RELATED,ESTABLISHED -m comment --comment "Direct packets associated with a known session to the RETURN chain." -j RETURN
-A neutron-openvswi-oba5cd56c-4 -j RETURN
-A neutron-openvswi-oba5cd56c-4 -m state --state INVALID -m comment --comment "Drop packets that appear related to an existing connection (e.g. TCP ACK/FIN) but do not have an entry in conntrack." -j DROP
-A neutron-openvswi-oba5cd56c-4 -m comment --comment "Send unmatched traffic to the fallback chain." -j neutron-openvswi-sg-fallback
-A neutron-openvswi-sg-chain -m physdev --physdev-in tapba5cd56c-46 --physdev-is-bridged -m comment --comment "Jump to the VM specific chain." -j neutron-openvswi-oba5cd56c-4

Pls help to give some advices about that.
Thanks a lot!