New Pi-Hole installation block internet

[robertsorensen]

I just installed Pi-Hole on a Raspberry Pi 4 and it's connected to my UDM Pro system.
Installation went fairly well (at least I think so). I can ping the Pi and I can access the Pi-Hole server.

After installation I wanted to check that it worked which I did by changing the DNS server in my Mac Studio on the WiFi network that I'm connected to. Once I did that I no longer could access the internet.
As soon as I added my router back in the DNS server list internet access was restored.
On the Pi-Hole Dashboard there were 0 Queries reported despite having tried several different web-sites.

I then tried on an iMac - did the same thing as change the DNS server to only include my Pi-Hole and it did work as in - I could browse to various website! Number of Queries went up (and the Dashboard now reports 11 queries and 5 blocked).
Then I did renew DCHP leases on the iMac and after that I could no longer access the internet from this machine either. (At least DCHP renewing is the only thing I think I did on that machine)

Both Mac's are on the same VLAN and same Network whereas the Pi-Hole is on the "Default" network on the UDM Pro.
My Mac Studio runs the latest version of Sonoma and the iMac runs Catalina.

I did run a pihole - d with the output here: https://tricorder.pi-hole.net/8RVvDBIi/

Any help and guidance is highly appreciated.

Thanks,

[nprampage]

You probably want the Pihole on the same network as your client (Mac) computers, but I don't think that's causing your main problem.

I would assume your UDM Pro is responsible for providing DHCP information to all the VLANs. Did you go to your VLAN configuration on the UDM Pro and manually configure the DNS server to be Pihole? This is under Settings/Networks/ then next to "DHCP Service Management" click on "Show Options."

After you've done this, you renew your DHCP lease on the Mac or other client on this network, and it should pick up the DNS server you specify above.

Apologies if I'm telling you something you already know; it wasn't clear to me if you'd done this from your description.

If this doesn't fix your issue, it may be time to let a dev analyze your debug log and step in for specifics.

[robertsorensen]

So I did figure out what I did wrong.
It turns out that under Settings-DNS I had "selected" default option "Allow only local requests" whereas when I'm using different VLAN on my setup the correct selection should be "respond only on interface eth0"