1

An illustration of a smiling stick figure with curly hair, talking to a browser, represented by the Firefox logo of a fox wrapped around a globe.

person: I want to go to https://example.com
browser: hmm, I don’t have an IP address for example.com cached. I’ll ask a resolver!

2

An illustration of a browser talking to a resolver, represented by a box with a smiley face holding a magnifying glass.

browser: what’s the IP for example.com?
resolver: hmm, I’ll look in my cache…

3

❤ DNS cache ❤
archive.org: 207.241.224.2
jvns.ca: 172.64.80.1

resolver: nope, I don’t have it cached, I need to ask the authoritative nameservers! I have the root nameserver IPs hardcoded.

note: we’re pretending the resolver has no .com domains cached. Normally it would use its cache to skip step 4.

4

An illustration of a browser talking to a root nameserver, represented by a box with a smiley face wearing three crowns.

resolver: What’s the IP for example.com?
root nameserver: ask a .com nameserver! It’s at a.gtld-servers.net

→ com NS a.gtld-servers.net.
ca NS a.ca-servers.net.
horse NS a.nic.horse.

(NS stands for “nameserver”)

5

An illustration of a browser talking to a .com nameserver, represented by a box with a smiley face wearing two crowns.

resolver: what’s the IP for example.com?
.com nameserver: ask an example.com. nameserver! It’s at a.iana-servers.net

list of DNS records:
neopets.com, NS, ns-42.awsdns-05.com.
→ example.com, NS, a.iana-servers.net.

6

An illustration of a browser talking to an example.com nameserver, represented by a box with a smiley face wearing one crown.

resolver: what’s the IP for example.com?
example.com nameserver: it’s 93.184.216.34!
resolver: great, I’ll tell the browser!

→ example.com, A, 93.184.216.34