DNS reset after a boot with MacOS Mojave

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10 points

DNS reset after a boot with MacOS Mojave

Hey all,

on my iMac Retina 4k 21.5” Late 2015 I have installed two months ago MacOS Mojave, applied the update to 10.4.2, and since the beginning I have the problem that after every boot (from shutdown or restart) the values I set in Network Preferences/Advanced/DNS are deleted and I have to re-enter them (I use 1.1.1.1 and 1.0.0.1 or 8.8.8.8 and 8.8.4.4).

I have tried every suggestion I found here, in Apple Support and around the web, but without luck.

In particular I tried :

- reset SMC

- reset NVRAM

- remove files from /Library/Preferences/SystemConfiguration (except com.Apple.Boot.plist)

- boot in safe mode

- create a new network location

- reset and flush the DNS cache

- reinstall latest combo update 10.14.2.

The problem is both with a Wi-Fi connection, as well as an Ethernet connection on a 100mb fiber line.

Any help you can give me is welcome.

Thanks in advance and best wishes for next festivities.

iMac Line (2012 and Later)

Posted on Dec 11, 2018 9:18 AM

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Answer 1

raina_b22

Community Specialist

Dec 13, 2018 8:24 AM in response to Deber

Hi Deber,

Thank you for posting in the Apple Support Communities. I understand you're finding that your DNS settings aren't retained after restarting.

You've done some great troubleshooting so far. I recommend trying a test to narrow things down further. Using the steps in this link, you can create a temporary administrator account, log in there, change the DNS using your preferred settings, reboot, and then check how the settings look in the test user. This will tell you if the issue is system-wide, or if it's user-specific. The link has some great next steps to try based on the results: How to test an issue in another user account on your Mac.

I hope these steps help.

Take care.

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Answer 2

Deber Author

Level 1

10 points

Dec 15, 2018 7:38 AM in response to raina_b22

Hi becky_s22,

many thanks for your reply.

I tried the suggestions from https://support.apple.com/en-us/HT204443 but I had no luck.

I created a new admin user, logged with it after a reboot, set my preferred DNS in Network Preferences, but after a restart and re-logging with this account, the DNS disappeared again :(

I noticed that configuring the IPv6 to ‘Link-local only’ is reset to ‘Automatically’ at every reboot too.

After investigating a lot on internet, I have discovered that the files that store these and other network datas are ~/private/var/run/resolv.conf and ~/Library/Preferences/SystemConfiguration/preferences.plist

These files, that should keep the network configuration after a restart, are always reset by a System process or daemon during the boot (maybe mDNSResponder ?).

Perhaps a permission problem or corrupted files ? I don’t think so as I often start the iMac in Safe Mode and the problem is always present.

I’ll try to search again for a solution and you’re always welcome if you have more suggestions.

Thanks again and have a nice weekend.

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DNS reset after a boot with MacOS Mojave

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