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I am experiencing inconsistent DNS resolution in macOS Monterey 12.5. I’ve noticed this issue with the same machine when it was running macOS Big Sur. I'm not on a VPN. I'm connected to a home network.

I am connecting at home via Wi-Fi and this only appears to happen at home.

This seems to randomly appear and resolve itself multiple times throughout the day (with random "downtime" up to 10 minutes). FWIW, during this "downtime", I'm still able to visit google.com in the browser without any issues.

I've tried the following things - none of which have any consistency fixing the problem.

  • Reconnecting to Wi-Fi.

  • Flushing cache via:

    sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder

  • Restarting the machine.

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Giacomo1968
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dillon
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    Odd. To me this is typically an internet connectivity issue. I assume that you are connecting to the internet via Wi-Fi, right? Has this ever not been the case? And where are you located when this happens? A known home or work network or somewhere else? – Giacomo1968 Aug 03 '22 at 21:12
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    Correct, I'm connected via Wi-Fi. I've only ever connected via Wi-Fi. I'm on a home network. This actually only happens on my home network now that I think about it. I have used my computer from other networks frequently enough to know this issue doesn't exists elsewhere. FWIW My PC doesn't have this issue and it's hardwired to the router. – dillon Aug 03 '22 at 21:55
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    Thanks for the info. Odd. Seems like Wi-Fi at home is spotty. Do you ever hook up USB 3.0 drives and devices to this Mac at home? USB 3.0 has a nasty habit of screwing up Wi-Fi and Bluetooth signals. Depends completely on the quality of the cables and proximity to the Mac. – Giacomo1968 Aug 03 '22 at 23:15
  • Do all of the DNS servers your home router recommends actually work? You can get a list of them in System Preferences -> Network pane -> Wi-Fi in the service list -> Advanced button (bottom right) -> DNS tab -> DNS Servers list, or by looking in /etc/resolv.conf ("nameserver" entries). You can test them with e.g. `host google.com 192.168.1.1` (where 192.168.1.1 is a server you want to test). – Gordon Davisson Aug 04 '22 at 04:31
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    I have a USB hub from Hiearcool Product# UCN3286 which has two USB3.0 ports that are in use. I'm going to disconnect the hub and keep everything else as is for today and see if any difference. Wild.. reading up on USB3.0 Wi-Fi interference. – dillon Aug 04 '22 at 14:11
  • The UCN3286 is also connected to a TESmart KVM switch that is sitting fairly close to my laptop so there's probably some merit to the USB3.0 interference hypothesis – dillon Aug 04 '22 at 14:15
  • @GordonDavisson my /etc/resolve.conf only has one entry and it does work `host google.com 192.168.0.1` – dillon Aug 04 '22 at 14:26
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    @Giacomo1968 The issue has not come back since disconnecting the Hiearcool UCN3286. Thank you for pointing out the potential for USB3.0 interference! – dillon Aug 05 '22 at 16:00
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    @dillon Happy this helped! Voting to close this question because while it is valid, the answer is what I posted here in this other question: [“Why does USB 3.0 interfere with 2.4GHz devices?”](https://superuser.com/a/1282595/167207) Duplicating an answer here is not worth it since that other thread is authoritative. FWIW, a cursory search for the [Hiearcool UCN3286](https://hiearcool.net/productDetail-730-629.html) shows it to be a bargain basement USB hub/dock. Typically the biggest thing those devices cut corners on is basic shielding. Stinks but that is what happens with discount items. – Giacomo1968 Aug 05 '22 at 16:08

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