DHCP replies are dropped at the subinterface

asked 2016-11-18 16:36:06 -0500

shahram gravatar image

My instance can not get an ip on a vlan provider network and I am not quite sure why. My iptables look ok for the vm tap, I see the reply from the dhcp server at the main interface level but I do not see it get passed to the sub-interface. Any additional troubleshooting guide will be greatly appreciated.

Thank you in advance.

here is the brctl output:

bridge name bridge id       STP enabled interfaces
brq855afcdd-fc      8000.d4ae52e8ae0c   no      em3.40
                            tap838dab94-47

here is the iptables List

  eneutron-linuxbri-sg-chain  all  --  anywhere             anywhere             PHYSDEV match --physdev-out tap838dab94-47 --physdev-is-bridged /* Direct traffic from the VM interface to the security group chain. */
neutron-linuxbri-sg-chain  all  --  anywhere             anywhere             PHYSDEV match --physdev-in tap838dab94-47 --physdev-is-bridged /* Direct traffic from the VM interface to the security group chain. */
neutron-linuxbri-o838dab94-4  all  --  anywhere             anywhere             PHYSDEV match --physdev-in tap838dab94-47 --physdev-is-bridged /* Direct incoming traffic from VM to the security group chain. */
Chain neutron-linuxbri-i838dab94-4 (1 references)
Chain neutron-linuxbri-o838dab94-4 (2 references)
neutron-linuxbri-s838dab94-4  all  --  anywhere             anywhere            
Chain neutron-linuxbri-s838dab94-4 (1 references)
neutron-linuxbri-i838dab94-4  all  --  anywhere             anywhere             PHYSDEV match --physdev-out tap838dab94-47 --physdev-is-bridged /* Jump to the VM specific chain. */
neutron-linuxbri-o838dab94-4  all  --  anywhere             anywhere             PHYSDEV match --physdev-in tap838dab94-47 --physdev-is-bridged /* Jump to the VM specific chain. */
nter code here

here is the traffic at main interface em3:

enter code here:
17:31:45.906424 fa:16:3e:0c:5b:16 > Broadcast, ethertype 802.1Q (0x8100), length 346: vlan 40, p 0, ethertype IPv4, 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fa:16:3e:0c:5b:16, length 300
17:31:45.906768 fa:16:3e:ea:6d:b0 > fa:16:3e:0c:5b:16, ethertype IPv4 (0x0800), length 371: 10.4.0.3.bootps > 10.4.0.4.bootpc: BOOTP/DHCP, Reply, length 329
17:31:45.906830 fa:16:3e:12:e0:3b > fa:16:3e:0c:5b:16, ethertype IPv4 (0x0800), length 371: 10.4.0.1.bootps > 10.4.0.4.bootpc: BOOTP/DHCP, Reply, length 329
17:31:45.906857 fa:16:3e:71:2e:fd > fa:16:3e:0c:5b:16, ethertype IPv4 (0x0800), length 371: 10.4.0.2.bootps > 10.4.0.4.bootpc: BOOTP/DHCP, Reply, length 329

here is the traffic at the subinterface em3.40

17:32:02.556582 fa:16:3e:0c:5b:16 > Broadcast, ethertype IPv4 (0x0800), length 342: 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fa:16:3e:0c:5b:16, length 300
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