Lately my home internet service has been experiencing brief periods of failure and I’m trying to understand what the root problem is and if there’s anything I can do to fix it.
I have two piholes running on my home network providing DNS service and blocking. Lately I’ve been encountering brief internet outages, approximately once a day for the last week. Work laptop disconnects from VPN saying no internet and other devices show no internet either. Cable modem doesn’t show it’s lost connection though, and logging into my router it shows it has internet connectivity. Trying to ping a website shows the dns resolution isn’t working. I can ping by IP address but not name. The outage usually resolves itself in approx 5 minutes, sometimes a little longer.
My piholes are setup to use Google, Cloudflare and Open DNS for dns service so I’m puzzled how my dns resolution suddenly starts failing. In theory if one’s down, it’ll use the others right? So how am I experiencing a dns outage? Is this a problem with something outside my network or something internal, or is there anything else I should do to diagnose and fix it?
Did you check for rate limits? I had some devices that’d bomb the pihole with repeated requests on every NXDOMAIN for a targeting/analytics domain. They then got rate limited by the pi hole which made the effect and rhe flood of requests permanent.
While you don’t seem to have a missbehaving device , you could still hit the rate limit.
I don’t see rate limit warning/errors in my logs but I did notice something I overlooked before. It’s only being reported by one pihole, the one running v6. The one running v5 doesn’t report anything similar and I’m not sure because v5 doesn’t report the error or because it’s not happening to that pihole. I’m seeing this error at the same time the outages occurred:
2025-10-23 02:02:48 CONNECTION_ERROR Connection error (1.0.0.1#53): failed to send UDP request (Network unreachable) 2025-10-22 14:03:54 CONNECTION_ERROR Connection error (2606:4700:4700::1111#53): failed to send UDP request (Network unreachable)The v5 pihole does see a huge spike in requests it’s trying to service during the outage just like the other pihole, so I suspect the same error is affecting it but it’s not logging it. The error does suggest Google’s dns server is unavailable or the internet as a whole. I would think the other servers I’ve got configured it would switch to though. If so I shouldn’t experience an outage then… maybe just a delay. But if it’s switching there aren’t any errors for those, so either the errors aren’t logged or my internet isn’t really out.