DevOps and cloud

Stage 2 · Lesson 3 of 8

DNS records and resolution

Networking for engineers

turns names like api.example.com into , like a phone book for the internet. Your machine asks a resolver, a server that finds the answer for you. The resolver works its way from the root servers to the .com servers, then to the servers that hold the domain's own records.

It then caches the answer for as long as the record's TTL (time to live) allows. Learn the DNS records you will actually set. An A record points a name at an address, and AAAA does the same for .

A CNAME points one name at another name. MX handles email, TXT holds verification strings, and NS says which servers are in charge of the domain. Pointing a domain at a server, a or a CDN is always a DNS change.

Common trapTTLs: lower a record's TTL well before a migration, or old answers stay cached for hours after you change it.

A question to check yourself, an AI practice session and 1 cheat sheet entry come with the full roadmap. Unlock

Resources for this stage

Start with

Practise

  • DevOps Exercises

    Answer its networking questions before reading the answers to find your gaps

Keep handy

  • NGINX Beginner's Guide

    Official guide to serving files and proxying to an app, the base of every config

  • MDN Web Docs

    The HTTP guides on headers, caching and status codes, for debugging proxies

Also worth your time

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