I am not sure but it looks as if apps on my Raspberry Pi perform dns lookups by querying 127.0.0.x first, which I assume is just a centralised cache.
I tried the following to set the underlying DNS servers that are used:
systemd-resolve --set-dns=2a00:1098:0:82:1000:3b:0:1 --set-dns=2001:4860:4860::6464 --set-dns=2001:4860:4860::64 --interface=eth0
service resolvconf restart
Does that look about right?
I tried
systemd-resolve --status
and
service resolvconf status
in the hope that that would show me the true current state of affairs and the results looked plausible. It says that you set up per-interface settings. I can’t see any global default though for values that could be inherited.
I am now using the Google public DNS64 servers for NAT64 since this is an IPv6-only machine. (Instead of the usual straight public DNS servers 2001:4860:4860::8888 and 2001:4860:4860::8844.)