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network.trr.mode = 3

chris.d.green
chris.d.green
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Hello Community! I have been a FF user for a couple of years now and really enjoy the browser - thanks for all the hard work. The last FF update to ver 76 has been a struggle as I use DoH and I set network.trr.mode = 3 (no non-DoH fallback allowed) however the update has broken this. I even completely reinstalled the OS (linux - pop) with a full clean install of FF with the same results. This is also the case on all my machines no it's for sure FF 76. Any ideas? Here are my config settings:

network.trr.mode = 3 network.trr.custom_uri = https://mozilla.cloudflare-dns.com/dns-query network.trr.bootstrapAddress - 1.1.1.1

No pages will load however when i set network.trr.mode back to '2' all works fine again.

Hello Community! I have been a FF user for a couple of years now and really enjoy the browser - thanks for all the hard work. The last FF update to ver 76 has been a struggle as I use DoH and I set network.trr.mode = 3 (no non-DoH fallback allowed) however the update has broken this. I even completely reinstalled the OS (linux - pop) with a full clean install of FF with the same results. This is also the case on all my machines no it's for sure FF 76. Any ideas? Here are my config settings: network.trr.mode = 3 network.trr.custom_uri = https://mozilla.cloudflare-dns.com/dns-query network.trr.bootstrapAddress - 1.1.1.1 No pages will load however when i set network.trr.mode back to '2' all works fine again.

Chosen solution

I figured it out finally and thought I would report back to close the loop. My Gateway has a feature called Web Filter and I had a block-session turned on for "Proxy Avoidance and Anonymizers". I saw the blocked traffic in the reports. Once I turned off the blocker, all was good. I'm still not sure why this issue only arose when upgrading to FF 76 but anyhow. Apologize for the confusion and thanks for your help.

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All Replies (3)

jscher2000 - Support Volunteer
jscher2000 - Support Volunteer
  • Top 25 Contributor
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Hi chris.d.green, I did a brief bug search, but it's not easy to spot ones that are new in Firefox 76. (https://bugzilla.mozilla.org/home)

You mentioned three preferences:

What do you have for

  • network.trr.uri

Mine shows the default of

https://mozilla.cloudflare-dns.com/dns-query

which is the same as your Custom URI. Maybe try removing the Custom URI?

- - - -

I wonder whether there might be a problem that DoH or that Cloudflare domain is blocked on the network you're using? Hopefully there would be some logging about that somewhere... maybe in the Browser Console? That's a separate little window from the tab-specific Web Console. More info: https://developer.mozilla.org/docs/Tools/Browser_Console

chris.d.green
chris.d.green Question owner
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For network.trr.uri I show "https://mozilla.cloudflare-dns.com/dns-query" 'network.trr.custom_uri' is actually blank. Just to be sure, I dropped in 'https://mozilla.cloudflare-dns.com/dns-query' to the network.trr.custom_uri and still a no-go.

chris.d.green
chris.d.green Question owner
more options

Chosen Solution

I figured it out finally and thought I would report back to close the loop. My Gateway has a feature called Web Filter and I had a block-session turned on for "Proxy Avoidance and Anonymizers". I saw the blocked traffic in the reports. Once I turned off the blocker, all was good. I'm still not sure why this issue only arose when upgrading to FF 76 but anyhow. Apologize for the confusion and thanks for your help.