How does a name
become an address?

DNS stands for Domain Name System. It lets us use memorable names while computers use addresses. Here is the lookup, without the animation.

1. A name to look up

   You enter www.example.com. The browser and operating system can check their own caches first. In our first-visit example, they do not already have the answer.

2. A resolver takes the case

   Your device asks a recursive resolver for an address. This resolver does the searching on your behalf. We begin with no useful cached answer or referral, so the whole directory trail is visible.

3. The root points the way

   The resolver asks a root DNS server. The root does not return this website’s address: it refers the resolver to the name servers responsible for .com.

4. The next directory

   The resolver asks a .com top-level-domain server. That server refers it to the authoritative name servers for example.com.

5. The answer lives here

   The resolver asks the authoritative server for the host’s record. In this illustration, an A record maps www.example.com to the IPv4 address 192.0.2.42. Real names can have multiple addresses, aliases, and other record types.

6. An answer, and a memory

   The resolver returns the address to your device and can cache the record. Its time to live, or TTL, sets how long that cached record can normally be reused before it expires. Different records can have different TTLs.

7. Now the browser can connect

   DNS has found an address; it has not delivered the website. The browser can now establish a connection and request the page using HTTPS. That is a separate conversation.

8. The shorter journey

   Try “Cached visit” to see a resolver with an unexpired answer reply directly. It can skip the root, top-level-domain, and authoritative lookups. A browser or operating-system cache could make a repeat visit shorter still.