Question How do you disable DoH in Firefox?

[rashmi]

I thought of trying Firefox, but there is no option to disable DoH in Firefox. You can disable DoH in Chrome and Edge, but Firefox DOH (OFF) says "Use your default DNS." Chrome and Edge with DoH disabled don't leak DNS when I use VPN, but Firefox leaks DNS with DoH default and OFF.

 

[Bot]

You can disable DoH in Firefox. Go to Options > General > Network Settings > Settings, then under "Enable DNS over HTTPS", select "Off". If you're still experiencing DNS leaks, it might be an issue with your VPN configuration rather than Firefox itself.

 

[Spiff]

@Bot,
The Firefox DNS over HTTPS settings are not in Settings\ General\ Network Settings, but in Settings\ Privacy & Security\ DNS over HTTPS. That is where one can select "Off".
https://support.mozilla.org/en-US/kb/dns-over-https

 

[silversurfer]

I thought of trying Firefox, but there is no option to disable DoH in Firefox. You can disable DoH in Chrome and Edge, but Firefox DOH (OFF) says "Use your default DNS." Chrome and Edge with DoH disabled don't leak DNS when I use VPN, but Firefox leaks DNS with DoH default and OFF.

Sounds the issue for you is the DNS leak in Firefox while using VPN?

Just check for Firefox settings related to WebRTC:

Use these instructions if you wish to manually disable WebRTC:

1. Type "about:config" into the address bar and hit Enter.
2. Click the button "I accept the risk!".
3. Type media.peerconnection.enabled in the search bar. Only one entry should appear.
4. Double-click on the entry to change it to false.

To enable WebRTC again, change it back to "true".

WebRTC

Learn about what WebRTC is and how to keep it from exposing your IP.

mullvad.net

 

[rashmi]

Sounds the issue for you is the DNS leak in Firefox while using VPN?

Just check for Firefox settings related to WebRTC:

In Firefox about:config, I've already disabled WebRTC.

 

[rashmi]

People have also reported a DNS leak issue here.

Firefox has DNS leak security issue

When I was using a proxy to surf the Internet, to ensure my security, I checked the DNS leak status. When I use Firefox, the query results show that my DNS is leaked and the DNS is my real DNS. However, when I use Chrome to query, there is no DNS leak. This is a serious security issue. Please...

connect.mozilla.org

 

[lokamoka820]

To disable DoH in Firefox, follow these steps:

1. Open Firefox: Open the Firefox browser on your device.
2. Click the menu button: Click the three horizontal lines () at the top right corner of the browser window.
3. Select Options: Click on “Options” from the drop-down menu.
4. Go to Network Settings: In the Options window, click on the “Network Settings” tab.
5. Scroll down to Enable DNS over HTTPS: Scroll down to the “Enable DNS over HTTPS” option.
6. Uncheck the box: Uncheck the box next to “Enable DNS over HTTPS” to disable DoH.
7. Click OK: Click the “OK” button to save your changes.

Alternatively, you can also disable DoH by using the about:config page:

1. Type about:config in the address bar: Type “about:config” in the address bar and press Enter.
2. Search for network.dns.disablePrefetch: Search for the “network.dns.disablePrefetch” preference.
3. Double-click to toggle: Double-click on the preference to toggle it to “true”.

Note: Disabling DoH may affect the performance and security of your internet connection. It is recommended to only disable DoH if you have a specific reason to do so, such as using a custom DNS server or experiencing issues with DoH.

 

[Spiff]

@lokamoka820,
What is your source?
What you wrote is similar to Bot's reply, but it is not what is in the Mozilla Support article.
https://support.mozilla.org/en-US/kb/dns-over-https

 

[SpiderWeb]

Ah! Go type this into your Firefox address bar:

about:config

Then search for network.trr.mode and set the value to 5. Here is a Firefox document explaining the settings.

Here is a useful Firefox document of other parameters that you might want to check also:

https://wiki.mozilla.org/Trusted_Recursive_Resolver

Then check what resolvers your Firefox browser is using via this useful website:

dnscheck.tools - check your dns resolvers

A tool to test for DNS leaks, DNSSEC validation, and more

www.dnscheck.tools

 

[rashmi]

Then search for network.trr.mode and set the value to 5.

Firefox has already set network.trr.mode to 5.

 

[lokamoka820]

@lokamoka820,
What is your source?
What you wrote is similar to Bot's reply, but it is not what is in the Mozilla Support article.
https://support.mozilla.org/en-US/kb/dns-over-https

Sorry for late answer, it was Brave AI.

 

[Spiff]

Sorry for late answer, it was Brave AI.

Ah, thanks very much.
So, two AI said similar things regarding Firefox DNS over HTTPS settings, not matching what is in the Mozilla Support article.
It seems that somehow both MalwareTips Bot and Brave AI based their responses on outdated documentation.

 

[lokamoka820]

Ah, thanks very much.
So, two AI said similar things regarding Firefox DNS over HTTPS settings, not matching what is in the Mozilla Support article.
It seems that somehow both MalwareTips Bot and Brave AI based their responses on outdated documentation.

I noticed that after I read your comment, I think I should check after AI answers, it is why I don't like AI.

 

[monkeylove]

Did you use this to check?

IP/DNS Detect

What is your IP, what is your DNS, check your torrent IP, what informations you send to websites.

ipleak.net

 

[rashmi]

Did you use this to check?

I used ipleak.net and browserleaks.com. Both websites show DNS leaks.

 

[monkeylove]

I used ipleak.net and browserleaks.com. Both websites show DNS leaks.

I just tried both and they show no leaks. All I did was follow the media.peerconnection.enabled setting.

You can probably install the Mullvad browser and Firefox Portable in the same machine and test those, too.

 

[rashmi]

I just tried both and they show no leaks. All I did was follow the media.peerconnection.enabled setting.

You can probably install the Mullvad browser and Firefox Portable in the same machine and test those, too.

I already have the media.peerconnection.enabled policy set to false. I tried Firefox Portable, and the test websites showed DNS leaks.

 

[monkeylove]

I already have the media.peerconnection.enabled policy set to false. I tried Firefox Portable, and the test websites showed DNS leaks.

You can probably bring a laptop to a place that uses another ISP and see what happens.

 

[rashmi]

You can probably bring a laptop to a place that uses another ISP and see what happens.

I tried my mobile's hotspot, which is a different ISP, and the outcome was the same. With DoH disabled, Chrome and Edge didn't leak DNS, but Firefox did.

 

[rashmi]

I use Clouflare DNS 1.1.1.1/1.0.0.1 with Automatic DoH Template in Windows 11 Settings: Network & Internet, Wi-Fi, Hardware Properties, and DNS Server Assignment. The Cloudflare website, 1.1.1.1 — the Internet’s Fastest, Privacy-First DNS Resolver, verified that I have DoH properly set.

It appears that DoH causes DNS leaks. If I set DoH to OFF, there are no DNS leaks.