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Comment by povertyworld | Hacker News Reader

I have a bunch of Facebook domains in my hosts, but for some reason Firefox 69.0 gets DNS from somewhere else and goes right through. Weird. The other stuff in hosts resolves correctly.

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It could be DNS over https, which Mozilla have been experimenting with.

https://support.mozilla.org/en-US/kb/firefox-dns-over-https

It wasn't on by default, but yeah, once I turned it on, it entirely bypassed hosts for everything, not just Facebook owned domains.

Check that "network.trr.mode" is set to "0" in "about:config" to disable firefox using DNS over HTTPS (DoH). It was introduced in Firefox 62 I think.

You're better off setting it to "5". From https://wiki.mozilla.org/Trusted_Recursive_Resolver :

"Set `network.trr.mode` to 2 to make DNS Over HTTPS the browser's first choice but use regular DNS as a fallback (0 is "off by default", 1 lets Firefox pick whichever is faster, 3 for TRR only mode, 5 to explicitly turn it off)."

Could you run `sudo killall -HUP mDNSResponder` and try again? It's possible that the DNS is cached.

No luck. I thought maybe it was cached somehow because of the way Facebook is linked from the start page, but so is Reddit, and putting Reddit in the hosts worked. Strangely, the hosts file doesn't seem to be read with Instagram either. I'm not sure what's going on here.

Is DNS-over-HTTPS on by default now?

It is not, just checked my install

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