Firefox not using IPv6 by default

Firefox@lemmy.ml – 34 points – 9 months ago

Websites like ipv6-test.com and test-ipv6.com say that my browser is using IPv4 by default.

This happens on Firefox and LibreWolf. I have tried creating a new profile without add-ons as well. Ungoogled Chromium uses IPv6 by default. If I go to ifconfig.io using Firefox, IPv4 is displayed. But if I use Ungoogled Chromium, IPv6 is displayed.

Is there a way to force IPv6?

I am not bothered by this, but using tools like ping6 and traceroute6 assures me that IPv6 routing is faster for, at least, one of my ISPs.

First check if you have ipv6 disabled in Firefox. I think there was a DNS issue on some lemmy instance a while ago where people were turning ipv6 off to work around that (was later fixed) or maybe I am misremembering where that was

Go to about:config then make sure that network.dns.disableIPv6 is false.

It is false, I have checked it.

Hmm, maybe this could be a DNS issue. Are you using DNS over HTTPS on Firefox (check on about:preferences#privacy? If so, what do you have the DNS provider set as?

Also what happens if you go to a website that is ipv6 only such as https://ip6only.me/? Does it fail to connect or does it then actually use ipv6?

I cannot reproduce that issue. Either site says IPv6 is working fine.

FF 121 on macOS.

How much faster?

Pinging my server in Frankfurt, DE, from my home in India, the ping speed using IPv4 is ~300ms, and using IPv6 is ~270ms.