This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Èròjà atẹ̀lélànà yii ni a ti fi pamọ́ fọ́jọ́ pípẹ́. Jọ̀wọ́ béèrè ìbéèrè titun bí o bá nílò ìrànwọ́.

network.trr.mode = 3

  • 3 àwọn èsì
  • 1 ní ìṣòro yìí
  • 1 view
  • Èsì tí ó kẹ́hìn lọ́wọ́ chris.d.green

more options

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.

Ọ̀nà àbáyọ tí a yàn

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.

Ka ìdáhùn ni ìṣètò kíkà 👍 0

All Replies (3)

more options

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

more options

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.

more options

Ọ̀nà àbáyọ Tí a Yàn

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.