I've set up an AdGuard Home server in my network. It provides the DNS-over-HTTPS service, I added it to my Firefox Network Settings configuration as https://adguar… (xem thêm)
I've set up an AdGuard Home server in my network. It provides the DNS-over-HTTPS service, I added it to my Firefox Network Settings configuration as https://adguard.example.com/dns-query and my machine has adguard.example.com in its /etc/hosts file.
The upstream AdGuard DNS server is my home router, which has several static DNS entries added for hosts in my network, e.g. foo.example.com pointing to 10.0.0.100.
During regular use, the domains resolve properly - when I navigate to http://foo.example.com everything works OK.
However when my machine is connected to VPN, the browser is unable to connect to http://foo.example.com, but it is still able to reach: http://10.0.0.100, regular internet as well as https://adguard.exaple.com (which is obtained from /etc/hosts).
This is on MacOS, using openconnect as a VPN client (and of course, the VPN connection changes the host DNS servers, this is what I'm trying to circumvent with Firefox' DoH feature).
I noticed one thing: with VPN, the use-application-dns.net resolves to something, without VPN it does not. I found this article, which mentions: "When any of these checks indicates a potential issue, Firefox will disable DoH for the remainder of the network session, unless the user has enabled the “DoH always” preference as mentioned above."
I have DoH explicitly enabled, the network.trr.mode is set to 2 (tried 3 as well, did not help). There's no such option as "DoH always" in the settings!
How do I make Firefox ignore the use-application-dns.net and always use my DNS server?