DNS

Everything and more that you wanted to know about DNS.

0 of 6 lessons complete

Practice in terminal (Ubuntu sandbox) ↗

Syllabus

  1. 01 What is DNS? Learn how DNS organizes and resolves distributed names and typed resource records.
  2. 02 DNS Components Learn how recursive resolvers, authoritative servers, zones, and resource records divide DNS responsibilities.
  3. 03 DNS Process Learn how a stub and recursive resolver use cache, referrals, glue, and authority to answer a DNS query.
  4. 04 /etc/hosts Learn how local hosts-file mappings participate in Linux name resolution and how to test them safely.
  5. 05 DNS Setup Learn how to choose, secure, validate, and operate authoritative or recursive DNS services.
  6. 06 DNS Tools Learn how to compare system resolution and direct DNS queries with getent, resolvectl, and dig.

Frequently Asked Questions

How does a DNS lookup work?

The course follows a query through clients, resolvers, root and authoritative name servers, explaining how components cooperate to return an answer.

Which DNS tools will I learn?

You will learn practical lookup and diagnostic concepts using tools such as dig and nslookup, along with local resolver configuration and /etc/hosts.

Is DNS only used for website addresses?

No. DNS stores multiple record types used for services, mail, verification, reverse lookups, and other forms of name-based discovery.