Comment 4 for bug 1865892

following the network issue troubleshooting: https://wiki.openstack.org/wiki/OpsGuide-Network-Troubleshooting

```
Finding a Failure in the Path
Use ping to quickly find where a failure exists in the network path. In an instance, first see whether you can ping an external host, such as google.com. If you can, then there shouldn't be a network problem at all.

If you can't, try pinging the IP address of the compute node where the instance is hosted. If you can ping this IP, then the problem is somewhere between the compute node and that compute node's gateway.

If you can't ping the IP address of the compute node, the problem is between the instance and the compute node. This includes the bridge connecting the compute node's main NIC with the vnet NIC of the instance.

One last test is to launch a second instance and see whether the two instances can ping each other. If they can, the issue might be related to the firewall on the compute node.
```

I can ping between 2 instances, I can ping the compute node where I run microstack. Everthing seems to poing out "then the problem is somewhere between the compute node and that compute node's gateway."

so next step was to use tcpdump:
```
tcpdump -i any -n -v 'icmp[icmptype] = icmp-echoreply or icmp[icmptype] = icmp-echo'
...
10.20.20.2 > 192.168.178.36: ICMP echo request, id 1588, seq 1, length 64
23:04:09.838803 IP (tos 0x0, ttl 64, id 8866, offset 0, flags [none], proto ICMP (1), length 84)
...
```

on the compute hosting microstack I could track the icmp messages from the VM 10.20.20.2 to the node 192.168.178.36 specifying the ip.

on the other test, ping 8.8.8.8 from the node was also visible in the logs:
```
192.168.222.6 > 8.8.8.8: ICMP echo request, id 1638, seq 1, length 64
23:07:05.330433 IP (tos 0x0, ttl 63, id 16531, offset 0, flags [DF], proto ICMP (1), length 84)
```

seems that it could also be related to some DNS relay as the ip would go through but not google.com

I also change the VM /etc/resolv.conf file `nameserver 8.8.8.8`
but this did not change much.

```
sudo killall dnsmasq
sudo systemctl restart snap.microstack*
```

did also not solve the issue. :(