Just got OPNsense set up. If you're on TekSavvy DSL, following https://docs.opnsense.org/manual/how-tos/ipv6_dsl.html then restarting your router and disconnect/reconnect cycling LAN devices will WORK to get you IPv6 (you may need to toggle Firefox's DoH to get fallback working on https://ipv6-test.com/ )... but it won't get you ICMPv6. Follow https://homenetworkguy.com/how-to/configure-ipv6-opnsense-with-isp-such-as-comcast-xfinity/ for that but set "any" as the destination address instead of "WAN address" or it won't work. #ipv6 #opnsense #network #networking
@rootbeerdan I will certainly grant that I have yet to figure out why my laptop's Firefox operates as "prefer IPv4 and fall back to IPv6 in under 1 second" rather than the "prefer IPv6 and fall back to IPv4 in under 1 second" like my desktop and how to fix it.
@ssokolow Disable DoH in the browser and it will use v6 more often. It’s been broken for years but nobody at Mozilla has had time to look into it. Note that you’ll break ECH if you do that (that might not be the case anymore, but it’s not widespread yet so eh).
But in general we just discourage Firefox usage entirely, the happy eyeballs implementation is poor and not RFC compliant (as you found out), and v4 traffic for us is more expensive than v6 (free).
@rootbeerdan I consider Firefox's userChrome.css and extended version of the WebExtensions API non-negotiable... but I suppose I could turn off DoH on the laptop, since I've already got a VPN just a click away in my Networks plasmoid.
@ssokolow I have never seen Firefox reliably respect happy eyeballs with DoH enabled in browser, something like 80% of all of our Firefox user agents in http request logs are IPv4 because of that issue despite having 100% v6 coverage