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VPN + Mozilla DNS over HTTPS

cgdevproject
cgdevproject
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Hello!

I use a VPN when I access the web and I recently updated my OS (Mac OS Tahoe). I updated Firefox and now DNS over HTTPS (DoH) is enabled in Firefox. When I have my VPN enabled, I cannot access the web, there is some problem with DNS resolution. I have changed my Firefox DoH settings to Standard (I have also used Strict) and have typically been unable to resolve web URLs correctly. There have been a few times that I have been able to use 'Standard' DoH strictness / settings and also use the VPN successfully at the same time, but typically when I have the VPN enabled Firefox cannot access whichever 'mozilla.cloudflare' address it is attempting to use for DNS resolution.

The VPN vendor suggested always using the VPN's DNS resolver. I have done this and I still have the same problem. What should I do to ensure that I have secure DNS and can successfully use a VPN?

Thank you.

Hello! I use a VPN when I access the web and I recently updated my OS (Mac OS Tahoe). I updated Firefox and now DNS over HTTPS (DoH) is enabled in Firefox. When I have my VPN enabled, I cannot access the web, there is some problem with DNS resolution. I have changed my Firefox DoH settings to Standard (I have also used Strict) and have typically been unable to resolve web URLs correctly. There have been a few times that I have been able to use 'Standard' DoH strictness / settings and also use the VPN successfully at the same time, but typically when I have the VPN enabled Firefox cannot access whichever 'mozilla.cloudflare' address it is attempting to use for DNS resolution. The VPN vendor suggested always using the VPN's DNS resolver. I have done this and I still have the same problem. What should I do to ensure that I have secure DNS and can successfully use a VPN? Thank you.

Modified by cgdevproject

All Replies (2)

jscher2000 - Support Volunteer
jscher2000 - Support Volunteer
  • Top 10 Contributor
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Have you tested the "Off" setting to confirm that Firefox can send DNS requests with the VPN running? See: Configure DNS over HTTPS protection levels in Firefox.

If you think about the reason for making DNS requests over HTTPS, sending them over your VPN might be equivalent. Both should be unreadable to your internet service provider, whether because the individual request is encrypted or because the VPN tunnel is encrypted.

cgdevproject
cgdevproject Question owner
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Hello,

Thank you for your prompt response to my question! I tried setting the "Off" setting for the DoH protection with the VPN turned on. The DNS resolution did not work for websites like "https://www.wikipedia.org/" or "https://www.google.com". What was odd is that I could use DuckDuckGo (it is set as my default search engine on Firefox), but I could not resolve other URLs. I could search the web via DuckDuckGo with the VPN on and search results would be returned. I would click on a link the the Google main search page or Wikipedia and the browser just hangs.

If I turn the VPN off and turn the DNS over HTTPS settings to "Maximum" protection (strict DoH via Cloudflare), I can use the web normally. My web connection functions correctly. I can connect to the VPN and have a valid / current subscription to the VPN. For some reason DNS does not work correctly with the VPN turned on. The sad thing is that the VPN vendor provides automated answers to my questions.

I do not know why the DNS requests are not resolved correctly while using the VPN. Thank you for spending some time thinking about my problem.

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