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?
I was doing some work on my server and noticed that when pi-hole was down, I couldn’t access the internet.
You’ve opted to take control over a critical piece of network infrastructure. This is to be expected.
There’s a reason DHCP provides for multiple DNS servers to be listed. Having redundant DNS servers is a common setup. So yes, multiple piholes if you want stability.
Just wanted to add onto your comment for clarity for others, the multiple servers are not redundancy so much as first come first serve, which is why your comment of multiple pi-holes is important.
If you were to list a pihole and say Google DNS as primary and secondary respectively, you may have some DNS queries responded to by Google. Negating the point of having a pi-hole or similar DNS service locally.
A secondary can be a docker container, another physical pi-hole (even a zero-w, which I personally don’t recommend being your only way to manage DNS, but is fine when you just need to do some maintenance on the primary).
One option is just do a temporary change on your PC to different DNS servers while you work on the stuff.
Otherwise a second PiHole set as the secondary DNS in DHCP would keep things online.
Another trick is setting up a guest/secondary AP that don’t use pi-hole. When your pihole is down, just switch to the secondary AP. Most routers can setup multiple APs, though not all can setup different dns server for the other APs.
I have my pi-hole setup as the upstream DNS in my router, with cloudflare as a secondary DNS. That way, all my devices always use the router for DNS (since that’s what is advertised in my DHCP) and the router then uses pi-hole if it’s available, or cloudflare if it isn’t. But the individual device doesn’t get to choose between different servers.
The vast majority of devices that allow setting multiple DNS servers do not strictly prioritise one over the other even if they label it as primary and secondary.
That’s why I don’t let every device decide individually. I know my router (FritzBox) prioritizes the pi-hole (it’s even called “preferred” and “alternative” DNS-Server in the UI)
Those labels are quite common too with systems that do not prioritize one over the other.
The ONLY DNS server you should have set on your network is a/the PiHole(s).
Not sure if this is common knowledge but Pi-hole can also run in a docker container, it doesn’t have to be a raspberry pi. I have it running on portainer on two different machine in my house. I’m a systems architect by trade so there no kill like overkill 😅
You might be a nerd when you have to schedule maintenance at your own house.
Use something like AdGuard or NextDNS as your secondary resolverCheck out the comment by @AtariDump@lemmy.world
The ONLY DNS server you should have set on your network is a/the PiHole(s).
Damn, fuck Windows. Fortunately I don’t have to use it.
The ONLY DNS server you should have set on your network is a/the PiHole(s).
That’s exactly what I do, since I never had any stability issues with my Pihole.
Primary and secondary dns is not a thing. There is no priority for DNS. Depending on the device it will use ether address and will only try the other on failure.
Windows calls them ‘preferred’ and ‘alternate’ DNS servers. That roughly translates to primary/secondary.
Yeah, that’s how they are named, my experience showed that the devices used whichever of the two they wanted.
It does not.
On Mikrotik I have a script that runs every 30sec. If pi-hole not responding, router switches to public cloudflare dns records, otherwise to pi-hole IP.
This setup works like a charm.
P.S. I am using Blocky, but it’s almost the same as Pi-Hole.
That’s why you usually have two piholes, or adguard homes
And can even synchronize them
ssh into your pi-hole if possible and try using commands systemctl status pihole-FTL Check the status, and if its disabled use the same command but with start instead of status. Also if this this your first time setup, double check that everything you did is correct, like the DNS setting on router, if the devices get the right DNS etc.
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Ssh to pihole.
$ pihole restartdnsusually works for meIf 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.
Can you send me some more information on this because this is the first I’ve ever heard that it would not automatically pick the fastest closest and most responsive DNS system available.
No remote DNS server will ever be as fast as one that is local
I tried this. Put a DNS override for Google.com for one but not the other Adguard instance. Then did a DNS lookup and the answer (ip) changed randomly form the correct one to the one I used for the override. I’m assuming the same goes for the scenario with the l public DNS as well. In any case, the response delay should be similar, since the local pi hole instance has to contact the upstream DNS server anyway.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I’ve seen in this thread:
Fewer Letters More Letters AP WiFi Access Point DNS Domain Name Service/System HA Home Assistant automation software ~ High Availability IP Internet Protocol LXC Linux Containers PiHole Network-wide ad-blocker (DNS sinkhole)
6 acronyms in this thread; the most compressed thread commented on today has 3 acronyms.
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Add another DNS server (1.1.1.1, for instance) to your DHCP options. Your DHCP clients will use 1.1.1.1 when the pi-hole isn’t responsive.
They will also use 1.1.1.1 whenever they want. The order is not guaranteed.
Hosts also tend to use the same one for some time, so if your pihole went down clients may still favor 1.1.1.1 even after it comes back up.
I don’t think this accomplishes what he wants. The router DHCP will assign the second DNS address as you mention, but the devices will select one at random, not as a backup/failover. So what happens is that devices sometimes go through the Pi-hole and sometimes go through the secondary DNS address and receive ads. The only real way I’m aware of is to have a second pi-hole for redundancy. Personally, I decided to use a cloud based service (NextDNS) for this exact reason. I didn’t want my families internet to rely on devices that I host.
I think it depends. In my limited experience, because I have not tested this thoroughly, most systems pick the first DNS adresses and only send requests to the second if first doesn’t respond.
This has lead at least a couple of times to extremely long timeouts making me think the system is unresponsive, especially with things like kerberos ssh login and such.
I personally set up my DHCP to provide pihole as primary, and my off site IPA master as secondary (so I still have internal split brain DNS working in case the entire VM host goes down).
Now I kinda want to test if that offsite DNS gets any requests in normal use. Maybe would explain some ad leaks on twitch.tv (likely twitch just using the same hosts for video and ads, but who knows).
Edit: If that is indeed the case, I’m not looking forward to maintaining another pihole offsite. Ehhh.
It is entirely the case.
DNS queries will go to all on the list, and use whatever responds first.
If you are seeing occasional ad leaks, this is why.
The ONLY DNS server you should have set on your network is a/the PiHole(s).
How many queries a month do you have? I’m at 15 days and I’m already at 750K. Do you pay for your service? I can do that, just curious what is common.
I’m at 30k blocked per day, over 100k queries per day.
This on a small 2 user network, with a handful of machines, but a fucking Samsung TV. That goddamn thing constantly pings all sorts of shit.
If I really restrict it (breaking some stuff on the TV), I can get to 35% of queries blocked per day, mostly from it.
Though nominal blocking kills the ads on the menu system, pretty well, making it much more responsive.
Wait, but then you cant tell if your device will use pihole even if its up. Afaik primary/secondary dns is not used in that order. I think best way is to set up 2nd pihole
Yeah this is the next best option, but a secondary pihole is the best, so you still get the dns blocking while the first one is down.
You listed cloudflare now (1.1.1.1) but I prefer https://www.quad9.net/ for the privacy and security.
The ONLY DNS server you should have set on your network is a/the PiHole(s).
Didn’t know that, thanks for clarification!
Then I suggest two piholes. :)
Does it really do that? I thought if pi-hole blocks it, it just says nothing here, normally a pc then looks up your secondary dns and then ads are back at it.
This was my experience when i did that.
Yes, your experience will be different if your DNS is being provided by another kind of DNS resolver. If you want a consistent pi-hole experience (and you can’t avoid downtime of your current pi-hole), add another pi-hole to your network and let that be your secondary DNS resolver.
No, that is not how DNS blocking works. It doesn’t just avoid responding, it responds but with a response that says that the domain does not exist or one that points to a different IP address.
The ONLY DNS server you should have set on your network is a/the PiHole(s).
Except when the ONLY pi-hole is down, which was the original OP’s whole question.
Umm, yea, if your DNS server is offline, how do your machines know how to resolve DNS names to IP addresses?
Which is why IP config has the capability for multiple DNS servers.
If this is surprising, you may wanna read up on your networking.
Why the extra snark? This person is asking a question. Easy to argue that he is trying to learn more about networking, why ostracize?
I think he realized that, he’s looking for a solution though.
