That doesn't always work, because servers aren't always used in strict order. For example, my default Kubuntu 19.10 installation flips the primary and secondar

That doesn't always work, because servers aren't always used in strict order. For example, my default Kubuntu 19.10 installation flips the primary and secondary if the primary is unresponsive for a while. Since my laptop takes a moment to establish a WiFi connection upon waking up, it always decides that the primary server is down and to default to the secondary server. It has currently been 3½ hours since my laptop queried its primary server and it has queried the secondary server over 1000 times in the past 24 hours despite the primary having 100% uptime. Most stub resolvers have an option to use strict order, but you can't rely on it as a network admin.