1811728 - dns leak http proxy

Status: RESOLVED INVALID

(Core :: Networking: DNS, defect)

Description

[XiJinping]

Steps to reproduce:

I'm using Firefox ESR 102.7.0 on Linux.
1.Configure HTTP(S) proxy for Firefox.
2.Visit https://ipleak.net

Actual results:

Ipleak.net detects my local (in mainland China) DNS server and proxy (in the US) DNS server.
This means that the Linux version of Firefox has a DNS leak when using an HTTP(S) proxy.

Expected results:

Ipleak.net can only detect DNS servers that are proxies.

Comment 1

[XiJinping]

I use the HTTP(S) proxy provided by Psiphon, but Firefox still experiences DNS leaks when using HTTP(S) proxies from other proxy software.

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Networking: DNS' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 3

[Andre Klapper]

1.Configure HTTP(S) proxy for Firefox.

How? Please provide steps to reproduce which leave no room for interpretation. Thanks!

Comment 4

[XiJinping]

(In reply to Andre Klapper from comment #3)

1.Configure HTTP(S) proxy for Firefox.

How? Please provide steps to reproduce which leave no room for interpretation. Thanks!

Use Psiphon or other software that provides HTTP proxy, I set the local HTTP proxy port of Psiphon to 2081.
The Firefox proxy configuration is shown in the following image.

https://i.imgur.com/VRvaFGP.png

This problem can also be reproduced on Firefox 109, but may only affect the Linux version of Firefox.
Also, when I tested another HTTP proxy for V2Ray, an anti-web censorship software, I also found DNS request leaks for Firefox, which is also configured the same way as above when using Psiphon.

Comment 5

[Valentin Gosu [:valentin]]

Could you paste the contents of about:support here?
Could you check if this problem still happens with a new profile (no addons)? https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

Thanks!

Comment 6

[XiJinping]

(In reply to Valentin Gosu [:valentin] (he/him) from comment #5)

Could you paste the contents of about:support here?
Could you check if this problem still happens with a new profile (no addons)? https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

Thanks!

After several tests, I found that the problem was caused by uBlock Origin, and after disabling it, the problem was solved.
Thank you all for your help!