Pihole be the DNS server in the whole network?

[jon]

If I understand what you are asking:

clients – (green) → IPFire – (red) → PiHole → Internet

PiHole is not the most secure device. The IPFire is much more secure since it is a hardened firewall.

So I would not configure things this way. And I would strongly recommend not to have PiHole connected to red (the Internet).

This is what I have:
Client (DNS) → PiHole (DNS) → IPFire (DNS) → to external DNS Server

See this post:

@jon

When reading through the Community posts you will see that PiHole is not recommended due to security issues. Since the pi-hole filters DNS records, DNSSEC is not possible from the client to the external DNS server (hope I explained this correctly).

EDIT:

@fstarter

So the clients connect to ipfire and have ipfire as DNS (blue, green)

And this is what I did to connect GREEN and BLUE to PiHole.

Pi-Hole and IPFire, which way round?

The pi-hole community might be able to help more than the IPFire community: