DNS and what happens when you type a URL
45 min · Intermediate
DNS (Domain Name System) is the internet's phone book: it turns a name like www.example.com into the IP address a computer needs. "What happens when you type a URL in the browser?" is one of the most asked placement questions, and DNS is its first step.
Topics in this lesson
- The DNS hierarchy: resolver, root, TLD and authoritative servers
- DNS caching and record types
- The full URL journey
- Model answer to "What happens when you type a URL?"
- Follow-up questions interviewers ask
Interview questions this lesson answers
- What is DNS?
- Why do we need DNS at all?
- What is a recursive resolver?
- What is the difference between a recursive and an iterative query?
- What does a root server do?
- What is a TLD?
- What is an authoritative name server?
- What is TTL in DNS?
- What is the difference between an A record and a CNAME?
- What is an MX record?
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