Hi David,
Vixie didn't invent DNS, but Paul Mockapetris might have. In the early days of ARPANET, each machine needed its own map of names to addresses. As the network grew this was difficult hence the DNS server came to be. You're looking for real pioneers like Ralph Ungermann or Charlie Bass. People who invented things and wrote United Patents and had them issued. In my humble oppinion.
Skeeter Wesinger
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