online.net: systemd Network Configuration with (r)DNS
This document will guide you through the process of setting up your online.net network addresses, DNS servers and rDNS records. For IPv4 we will use systemd-networkd (part of systemd) and odhcp6c (OpenWrt embedded DHCPv6-client) together with iproute2 for IPv6. For DNS we'll use systemd-resolved.
systemd is the default init process on Arch Linux, Debian GNU/Linux, Fedora, Ubuntu and more. iproute2 is also preinstalled there. So, if you're using a distribution that uses systemd, this tutorial should work for you. If you're using Gentoo Linux first make sure that you're using systemd.