It has certainly evolved to be pretty complicated. You have whatever libc chooses to do with getaddrinfo(), nsswitch.conf, resolv.conf, systemd-resolved, variou

It has certainly evolved to be pretty complicated. You have whatever libc chooses to do with getaddrinfo(), nsswitch.conf, resolv.conf, systemd-resolved, various pieces of software (docker, vpns, wsl), and so on, all trying to control the local resolver.