DNS Issue

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DNS Issue

Since installing Big Sur, my internet connection has been slow and kept dropping out. I changed the DNS settings to OpenDNS servers and it was back to normal. Then it went slow again and dropping out again. I checked the DNS settings and it had deleted mine and restored the old ones I had removed. This keeps happening. I tried flushing the cache with Terminal command: sudo killall -HUP mDNSResponder

That hasn't helped - it still removes my DNS settings and restores the previous ones that don't work. Anybody got any ideas?

Posted on Feb 14, 2021 4:09 AM

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Answer 1

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Paul_74

Level 1

42 points

Feb 14, 2021 5:09 AM in response to Dogglebird

I suspect when DHCP renews your IP address lease, its also updating your DNS server. However you should be able to specify a separate DNS server whilst using DHCP.

If you are at home, have you tried manually setting an IP address rather than using DHCP? Not ideal I know. Doing this will tell you whether its DHCP updating the DNS server when the lease renews.

Another option is to modify your router to use an alternative DNS provider than your ISPs.

If memory serves Big Sur introduced an option under the WiFi tab called "Show legacy networks and options". Maybe try turning this on if its off.

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Answer 2

Dogglebird Author

Level 1

5 points

Feb 14, 2021 5:55 AM in response to Paul_74

Thanks once again. The VPN provider have been next to useless when asked about this issue. They reply quickly, but it's all in computer gobbledegook and if you don't understand what they are saying, they lose interest.

Following your advice, I checked the VPN application "Preferences" and there was a box ticked which said "Use VPN's DNS" - whatever that means. I unchecked it and it presented me with a box to insert the IPs of preferred DNS servers. I have done that so - just maybe - that's fixed it. I will know within hours.

Once again, your input is much appreciated.

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Answer 3

Paul_74

Level 1

42 points

Feb 14, 2021 5:45 AM in response to Dogglebird

No worries. I know Big Sur implemented a bunch of changes to improve security including networking. It may be worthwhile looking on your VPN provider's web site to see if they have an update and/or post on their forum. I'd also check you have the latest Big Sur updates installed.

It may also be worthwhile having a look at the VPN application to see if the DNS servers can be set in there.

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Answer 4

Dogglebird Author

Level 1

5 points

Feb 14, 2021 5:18 AM in response to Paul_74

Thanks, Paul. Sorry, but I am a dummy when it comes to computers. I have only just discovered what DNS is and I have no clue what DHCP is or how to specify a separate DNS server etc. and the rest of that sentence is over my head. :(

I use a VPN all the time, so that determines my IP. I have contacted my ISP and they say the router they have supplied can't be adjusted.

I have tried the last suggestion - I have turned on the WiFi tab called "Show legacy networks and options" - I'll see if that makes a difference.

Your response is much appreciated.

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DNS Issue

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