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?
Wait, both are DHCP providers? Admittedly, I haven’t looked too deep at pihole clusters - but do they synchronize their leases? If not, there’s a chance you might have duplicate IPs which can cause some interesting network behaviors.
If your logs say both are having issues at the same time, I’d go with the second troubleshooting option - accept DHCP, but statically set DNS to the same servers your Piholes use.
If there’s an issue, it’s with the upstream DNS (reachability or their rate limiting)
No duplicate IP concerns. They both work with the same static list and when they need to assign dynamically - because requester isn’t in the static list - they assign from a non-overlapping range. Works well.
I think it is the upstream dns but strangely only the v6 pihole is reporting it, not my v5 one.