One or more of this system's 2 nameservers are dead!

[BradB]

I've been banging my head against the wall with this message. Only one of my internal DNS would respond. Usually IPv4 would work and IPv6 wouldn't. In my troubleshooting I managed to flip-flop that but had difficulty recreating the conditions to make that stick. Everything was super inconsistent.

Unifi Ad blocking was the problem. Paused that and everything works great. Just posting this for anyone else searching in the future. I'm still trying to figure why this is happening and will update if I figure it out. Will probably spin up pi-hole later just to compare.

 

[peterblaise]

Thank you for troubleshooting and reporting.

I find that DNSBench is like SpinRite in that they both presume honest,
industry-standard rules-following devices.

Unlike ValiDrive which presumes a fake drive, perhaps we need a
ValiDNS program to also hunt down DNS redirection or other filtering
or DNS server query interference.

I'm researching "... Unifi Ad blocking ..." right now - interesting:

Google Search

We probably should make a list or hashtag for situations where
DNSBench reports no direct access to DNS servers, yet the Internet is
working fine for folks.

Thanks again.

 

[BradB]

Thank you for troubleshooting and reporting.

I find that DNSBench is like SpinRite in that they both presume honest,
industry-standard rules-following devices.

Unlike ValiDrive which presumes a fake drive, perhaps we need a
ValiDNS program to also hunt down DNS redirection or other filtering
or DNS server query interference.

I'm researching "... Unifi Ad blocking ..." right now - interesting:

Google Search

We probably should make a list or hashtag for situations where
DNSBench reports no direct access to DNS servers, yet the Internet is
working fine for folks.

Thanks again.

Yes I started reading some of that myself but something else came up. Planning on messing with it more soon.