Speaking as someone who has debugged a considerable number of DNS problems, recurring from the root as described in the post is the only dependable way to deter

Speaking as someone who has debugged a considerable number of DNS problems, recurring from the root as described in the post is the only dependable way to determine a domain's authoritative servers. I've seen every alternative method (`dig NS $DOMAIN`, `dig SOA $DOMAIN`, `whois $DOMAIN`) give the wrong answer in some cases.