I assume "split DNS" requires extra software anyway and is going to update `/etc/resolv.conf`. So far I have been using `dnsmasq` which is pretty common in the industry although not something seamless.
No; support is baked into the default OS resolvers if you like, but obviously you can also use outbound software to achieve it too. The stuff in /etc/resolv.conf have not been "the whole story" in Linux name resolution ever since systemd, and at times has really tripped me up.
