We use the 2nd address from the subnet to serve Dnsmasq for IPv4 dns queries. The problem is, dnsmasq also uses that address to communicate with the upstream dns servers. That results in a packet with a source address as the private ip (2nd address of the subnet) AND we were not NATting it. Therefore, we never got the response back when we use the IPv4 Upstream DNS server. This was not visible to the VM because it was querying dnsmasq in parallel for all the available addresses AND Dnsmasq was responding them, whichever comes first, was accepted. Now, we start to properly NAT the DNS queries as well, this way, dnsmasq can properly communicate with upstream dns servers.
15 KiB
15 KiB