When Pi-hole is down? - Lemmy.World

I have an asus router with a pi-hole on the network. I was doing some work on my server and noticed that when pi-hole was down, I couldn’t access the internet. I was looking for some ideas online how to deal with this, but they said to have a second pihole on the network in case one is offline. Is that the only way to do it? Is there any way to have the network go back to normal if the pihole is offline?

If you're router has a failover DNS option, usually listed as DNS 2, I would set something like quad 9 as your backup DNS. Address is 9.9.9.9.

If you don't want to do that, then having a second instance of pihole running as the secondary DNS is pretty much your only good option

That’s not how the two entries for DNS works. Devices will use both rather randomly, and therefore some requests will not be filtered.

The best way is to run two instances for redundancy.

Yeah, looks like you don't know what you're talking about.

The second ipv4 DNS address is for redundancy and every network connected system will use the first one as long as it responds.

It's perfectly fine to have a single pihole and use something like quad9 as a failover in the unlikely event that your pihole goes down unexpectedly.

Actually they do know what they’re talking about. Configuring DHCP with multiple DNS servers isn’t for failover, it’s for redundancy. The result is ultimately operating system dependent, but modern Windows operating systems will query all configured DNS servers in parallel and will accept the first answer it receives. So if you configure your Pihole as one DNS server and a public DNS server as a second, a lot of your traffic will just bypass your Pihole ad filtering entirely.

Proof?

I read 15 different sites about DNS and not a one of them claimed anything like this. They universally all stated that your network attached devices would use the 1st one unless it didn't respond and only use the 2nd one if the 1st one did not.

So once again, I ask "Can you send me some more information on this" and not just claim it without any backup information?

I apologize if I am coming off rude, just my BS meter is getting close to the red zone and I would really appreciate some reliable evidence.

On the left is the DNS server that DHCP sets first. On the right is one it sets second.

This is a mixed machine network (Windows, MacOS, iOS, Android etc).

My clients will mostly pick option number one, but as you can see it's not a guarantee at all.