The issue I am facing:
Some of my devices have intermittent connection issues, sometimes with local devices sometimes with external internet sites. Currently I have an iPad which can access the internet but cannot access two internal servers I have. Other devices on my network can access these servers just fine.
Details about my system:
I have a Raspberry Pi with DietPi installed and PiHole set up. The Raspberry Pi is connected to my router via Ethernet. My router has DHCP disabled and I have DNS and DHCP running on PiHole. I have a second Raspberry Pi running a backup PiHole DNS server which are synced with Gravity-Sync this second Pi also has Home assistant running.
What I have changed since installing Pi-hole:
Not aware of changing anything recently, other than upgrading PiHole
My iPad is currently unable to ping two servers I have, one Unraid server and one Raspberry Pi (with Home Assistant). Other devices I have can ping and connect to these two servers. Can someone give me some hints on how to trouble shoot this please.
These "other devices" that you have that can reach your servers. Do they connect to the network with WiFi as well, or are they cabled devices? I think that it is strange that only your iPad has issues. It's either an issue specific to the iPad, or there is an issue with how your iPad tries to connect to the net (example WiFi). If it can't even ping, then it's either segmented or has issues receiving IP from the DHCP server. It's kind of hard to give you hints without more info regarding your network/setup.
iOS devices are very difficult to configure IPv6. Actually, there is no configuration on them, and they prefer them.
If their network is is not using IPv6 but allows passthrough they will have issues.
e.g. my iOS devices connect to my wifi using IPv6. All of them. But that took a lot of reading and a fresh install of Bullseye and then installing Pi-hole and doing the IPv6 at the start.
I’m still struggling with this issue. To me the effects seem very random. It is not always the same devices that cannot connect to other devices. Sometimes they loose connection to the internet , sometimes they loose connection to other devices devices on the local network. I’ve delayed responding because I’ve also got a Netgear Orbi WiFi system, and I wondered whether that was causing issues, I did a factory reset on the Orbi system and it has not helped. I’ve had the same network system in place including PiHole for well over a year now and I wonder if a recent PiHole update is causing issues. Tonight the system broke down again. I tried a pihole restartdns and that got everything working again.
Is there anyway to downgrade PiHole to a previous version?
The latest update seems to have caused some errors, but my Pi-Hole setup works great overall. But the fact that pihole restartdns resolved your issue, Pi-Hole is definitely causing issues. If you want to try troubleshoot your Pi-Hole, try looking into the log files and see if there is anything interesting in there that you find. I'm not a Linux system pro, or a programmer. Although I do have some limited knowledge in those fields. I am good however when it comes to computer networks. If you feel okay to share a basic description of your network topology, I could try to help you figure it out.
It feels like the PiHole DHCP server was not renewing DHCP leases. I’ve disabled PiHole for now and given DHCP and DNS back to my router. I’ll try this for a few days, if I’ve still got issues I’ll put it down to the NetGear Orbi. If not I’ll put it down to PiHole. If I think it is PiHole I fire it back up again and try some troubleshooting. But I want to rule out the Orbi at the moment.
Have you tried running with your router as DHCP, and Pi-Hole as DNS? If there is issue with running DHCP with Pi-Hole, then try running DHCP on your router. That's how I run it, and there are no issues whatsoever.
I know that my friend runs DHCP on Pi-Hole because his router doesn't allow to change DHCP-settings to manually configure DNS IP. But if your router allows you to freely configure DHCP as you like, then there is no real benefit from running DHCP on your Pi-Hole. Just enable DHCP on your router, configure the DNS server in DHCP-settings to Pi-Hole IP-address, and you're good to go.
Yeah, I cannot change DNS settings on my router, so I ended up running DHCP on PiHole. I’m on Plusnet in the UK. I’ve got a spare Plusnet router so I think I’ll flash openWRT on it so I can change the DNS settings. I’m away for a few days so I’ll leave PIHole off for a while just to make sure it’s not an issue with the Orbi WiFi.
Ok, so a bit of an update. I disabled PiHole and everything was back to working properly, so I’m happy the Netgear Orbi is not the cause. I suspected the issue was with the PiHole DHCP server not reallocating IP addresses after the lease had expired. I had a router with openWRT flashed to it, I was using it as a switch, so set this up with DHCP server and got it to advertise my PiHole DNS server. It all seems to be working nicely now, with DHCP addresses being given out properly, and all devices using PiHole as their DNS server.
I wonder why the PiHole DHCP server was activity like this. It has been fine for a year or so, so I suspect a recent PiHole update has broken something.
Probably something to do with PiHole DHCP in recent updates. I've seen some other threads with people having issues with DHCP on PiHole. If you managed to get it to work with a OpenWRT router then I recommend that you keep using that as your DHCP.