[ubercow13]

That's in libc. I guess that's below the application later, but doesn't some code elect to not use that, like go programs? I might be mistaken

[JoshuaRLi]

At least on linux, go's native resolver follows a sane subset of glibc conventions like parsing /etc/nsswitch.conf, /etc/resolv.conf, /etc/hosts [1]. As long as your dns configuration is defined there, you won't notice much of a difference between go programs using go's resolver and programs making glibc library calls for dns stuff.

1: https://jrl.ninja/etc/2/strace-go-1.12.3.txt

src for above: https://jrl.ninja/etc/2/getaddrinfo.go.txt