Why is mDNSResponder not responding?

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Level 1

18 points

Why is mDNSResponder not responding?

Sometime in the past month or so, my mac mini (M1 2020) stopped responding to multicast DNS requests. To my recollection, very little has changed with the system during this time. The system is connected on both Wi-Fi and Ethernet to the same network.

I've tried all the usual troubleshooting, including:

Restart the machine
Update from macOS Sonoma 14.5 to 14.6
`sudo killall -HUP mDNSResponder`
Disconnect Ethernet and restart
Disable Wi-Fi and restart
Remove and reinstall both network adapters (Wi-Fi and Ethernet)
Scanning console logs for errors
Confirm firewall is disabled
Verify 'hostname' command returns 'minamoto.lan'

I've managed to get zero successful resolutions of the name, "minamoto.local" on localhost or on another mac on the network. mDNS resolves for other hosts on the network.

Looking at the console logs, I do see it receiving requests and responding to them, but they simply do not resolve. Because of the privacy masking, I can't easily tell where the requests come from, what they're querying, or what responses are returned, only that it seems to be functioning. The only errors I observe from the service I can also observe on my other mac, where mDNS is working.

Are there any other options to "reset" mDNSResponder or troubleshoot the issue?

Mac mini

Posted on Aug 4, 2024 8:30 AM

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Answer 1

Top-ranking reply

jaraco Author

Level 1

18 points

Aug 4, 2024 8:48 AM in response to jaraco

Well, heck. After spending hours troubleshooting, I thought to check the Sharing page, and there I see the problem:

Apparently something happened to cause macOS to replace `minamoto.local` with `minamoto-2.local`. Could it be that when I connected the ethernet and Wi-Fi both on the same network that it detected a conflict with itself and renamed itself to avoid the conflict? Connecting both network adapters was something that I did do in the past couple of months, although I know the mdns was responding to the original name after doing so (it was one of the explicit checks I did). So maybe the self-conflict only arose later, perhaps by a router reboot or a host reboot.

After resetting that name to the correct "minamoto.local", the mDNS is now responding to the name as expected.

I'll continue to monitor it and see if it renames itself again.

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