Why does Paul Mockapetris say domain names run from most specific to least specific?

Paul Mockapetris rejects the idea that names like maps.google.com are backwards. Putting the most specific label first lets a computer guess the rest: typing a local machine name can be completed from nearby context, while starting with .com narrows things only to hundreds of millions of names. He told Ryan Peterman he makes no apologies for the choice, though many people think he got it wrong.

• Mockapetris notes that actual server lookups travel the opposite way, starting at the root and moving down.
• Xerox PARC's naming system at the time used a fixed three levels, which Mockapetris considered a mistake; DNS allows any reasonable depth.

▸In their words

“You say inverted. I say it's an obvious choice.” Paul Mockapetris · at 9:32 — open in the transcript →

Source: our own transcription of the episode. The full conversation is on Ryan Peterman (2026-10-19). Read the whole episode summary →

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