Prerequisites
Vault · 88 words · 1 min read
DNS: The Internet's Phone Book
How a distributed naming system made IP addresses human-friendly and the web navigable.
The Naming Problem
By the mid-1980s, the internet had outgrown its hosts.txt file — a single text file that mapped hostnames to IP addresses, maintained by hand at Stanford. Paul Mockapetris designed DNS as a distributed, hierarchical database that could scale to millions of names.
How It Works
you type: blog.example.com
→ Root server: "Ask the .com server"
→ .com server: "Ask example.com's nameserver"
→ example.com NS: "blog.example.com is at 93.184.216.34"DNS is one of the most critical pieces of internet infrastructure. Every HTTP request starts with a DNS lookup. Every email delivery depends on MX records. It’s a distributed database that handles trillions of queries per day with remarkable reliability.