Forget learning to debug DNS issues, most developers I work with have no concept of how DNS works even a little bit.

I can forgive them not understanding specific client behaviors of their chosen language, framework, or OS as far as TTLs (or if they even cache at all) and other stuff like that, cause those implementation details often vary and are abstracted away. But if I need to explain the difference between a CNAME and an HTTP redirect one more time…well it’ll probably be next week.