You are obviously getting nowhere with your current configuration, so I suggest you try the following:
- Disable the port forwarding and the iptable rules you have already applied.
- Change your Primary DNS Server (DHCP settings) to 8.8.8.8 (yes, NOT the pihole)
Now all DNS requests should go directly to 8.8.8.8, so nothing will appear in the pihole log.
Start configuring the firewall to redirect requests from all systems to IP 8.8.8.8 port 53 to your pihole
If you get it right, requests your system(s) make will start appearing in the pihole log. To look dynamically @ the pihole log, you can use either tools / tail pihole log from the pihole admin console or look at this topic to get a dynamic view.
As soon as all of the DNS requests from all machines appear in the pihole log, you can change your Primary DNS Server (DHCP settings) back to the pihole and duplicate, if appropriate, the rules you have configured for 8.8.4.4.
From what I read in your comments, you appear to be ignoring the fact that most DNS tools will always use the default DNS server (the pihole in your current configuration). Always specify the DNS server to use when using nlsookup or dig.
Some examples:
nslookup -query=A doubleclick.net 208.67.222.222 : gets the IPv4 address for doubleclick.net from server 208.67.222.222 (OpenDNS server)
dig @208.67.222.222 -p 53 A doubleclick.net : gets the IPv4 addresses for doubleclick.net from server 208.67.222.222 (OpenDNS server)
dig @208.67.222.222 -p 53 AAAA doubleclick.net : gets the IPv6 addresses for doubleclick.net from server 208.67.222.222 (OpenDNS server)