Firefox disable QUIC protocol

I’ve been trying to disable QUIC protocol but Firefox is still trying to use it…
I noticed that it is trying to bypass my DNS server resolving names directly through QUIC.

Is this the right option ?

user_pref("network.http.http3.enabled", false); ← Disabling QUIC

Really weird because I’m observing connections to UDP/443 to the following IPs: (not sure what IP is this) < a lot of IPs from this network (Cloudflare)

If someone know how to do it, kindly share, thanks.

I found disabling http3 made all the google properties load faster.

hm, good to know… But is it working for you ? I disabled it using the method mentioned in my first post but it is definitely not disabled… Perhaps some hardcoded thing in the browser ?


As you can see above, more than 4k attempts to use UDP 443… And increasing…

what are you using/doing to generate that graph?

Graylog server running in a raspberry pi 4b.
Graylog is a Syslog/Netflow server that uses mongodb and elasticsearch/or/opensearch.

So, basically my home is my lab, and I use it to apply these configurations to some customers.
I’m exporting logs and netflow data from my devices to it…

I removed some sensitive data, such as countries names I’m blocking through geoIP so people don’t get upset because I’m blocking their countries.
Removed some hostnames and IP addresses too.

You know the forum software will poll for changes

You can go to any page you are on and bring up developer tools to see what connections are being made and if they are failing

This shouldn’t be necessary because I’m disabling right at the user.js file ?
I’ll try to confirm what website is triggering it, but even if I find out, this shouldn’t be happening.
There is something hardcoded in the browser, or the network.http.http3.enabled is not working…

If you can find the page that is doing http/3 let me know and I will look on my end as well