1600976 - network.trr.mode=3 prevents the user from accessing any website after reconnecting to the network

Status: RESOLVED INVALID

(Core :: Networking: DNS, defect)

Description

[Daniel Cicas [:dcicas], Release QA]

Attachment: log.txt-main.9704.moz_log

Affected versions

• Fx 70.0.1
  Fx 71.0b12

Affected platforms

• mac OS 10.15
  Ubuntu 18.04
  Windows 10
  Windows 7

Steps to reproduce
Preconditions
The Doh add-on is installed and the network.trr.mode pref value is 2.
The "doh-rollout.enabled" boolean pref was added with the "true" value.

1. Disconnect from the network.
2. Navigate to the "about:config" page.
3. Navigate to the "about:config" page and change the network.trr.mode pref value to 3.
4. Reconnect to the network.
5. Navigate to the "about:config" page and observe the network.trr.mode pref value.

Expected result

• You are able to navigate the internet after reconnecting and setting trr to 3.

Actual result

• The pref stays at 3 but you can no longer visit websites.

Comment 1

[Valentin Gosu [:valentin] (he/him)]

Hi Daniel,

Looking at the logs it seems to me that you're setting mode3 without configuring a bootstrap address. Is this correct?
Normally when enabling mode 3, network.trr.bootstrapAddress should be set to 104.16.249.249 or an IP that corresponds to the DoH server https://dns.google/query?name=mozilla.cloudflare-dns.com

Comment 2

[13hu]

(In reply to Valentin Gosu [:valentin] (he/him) from comment #1)

Hi Daniel,

Looking at the logs it seems to me that you're setting mode3 without configuring a bootstrap address. Is this correct?
Normally when enabling mode 3, network.trr.bootstrapAddress should be set to 104.16.249.249 or an IP that corresponds to the DoH server https://dns.google/query?name=mozilla.cloudflare-dns.com

My understanding was network.trr.mode of 3 means there is no fallback or bootstrap from the DoH resolvers.
https://bagder.github.io/TRRprefs/

I think I'm also encountering this issue after upgrading to FF 71.0
I reported at bug 1601147

I would say this is critical as it completely prevents resolving if TRR 3

Comment 4

[13hu]

(In reply to Valentin Gosu [:valentin] (he/him) from comment #1)

Hi Daniel,

Looking at the logs it seems to me that you're setting mode3 without configuring a bootstrap address. Is this correct?
Normally when enabling mode 3, network.trr.bootstrapAddress should be set to 104.16.249.249 or an IP that corresponds to the DoH server https://dns.google/query?name=mozilla.cloudflare-dns.com

Valentin is correct, confirmed setting network.trr.bootstrapAddress is required for continued resolution.

This should definitely be documented somewhere if it isn't already.

Comment 5

[Valentin Gosu [:valentin] (he/him)]

(In reply to 13hu from comment #4)

(In reply to Valentin Gosu [:valentin] (he/him) from comment #1)

Hi Daniel,

Looking at the logs it seems to me that you're setting mode3 without configuring a bootstrap address. Is this correct?
Normally when enabling mode 3, network.trr.bootstrapAddress should be set to 104.16.249.249 or an IP that corresponds to the DoH server https://dns.google/query?name=mozilla.cloudflare-dns.com

Valentin is correct, confirmed setting network.trr.bootstrapAddress is required for continued resolution.
This should definitely be documented somewhere if it isn't already.

Mode 3 hasn't been officially released yet - when changing things in about:config there is always a risk of breakage.
That being said, some documentation of the prefs is available here: https://wiki.mozilla.org/Trusted_Recursive_Resolver#network.trr.mode

Comment 6

[Daniel Cicas [:dcicas], Release QA]

Hello,

Sorry for the late reply, yes network.trr.bootstrapAddress was not set to anything when the issue was encountered. As a side-note for the less experienced people shouldn't the pref come with the IP address by default?

Comment 7

[Valentin Gosu [:valentin] (he/him)]

(In reply to Daniel Cicas [:dcicas], Release QA from comment #6)

Hello,

Sorry for the late reply, yes network.trr.bootstrapAddress was not set to anything when the issue was encountered. As a side-note for the less experienced people shouldn't the pref come with the IP address by default?

The IP may change, hardcoding it in Firefox is not great. We have a new bootstrapping mechanism that is supposed to land in Nightly soon.