Stage 1 · Lesson 5 of 7
DNS records
(Domain Name System) turns names such as app.example.com into IP addresses. An A record points a name at an address, AAAA at an IPv6 address, and a CNAME points one name at another name. TTL (time to live) tells resolvers how long they may cache an answer, which is why DNS changes sometimes seem slow.
In the cloud, custom domains, , managed certificates and email all depend on the right records. Learn to query records with dig or nslookup so you can check what the world actually sees.
Common trapchanging a record with a long TTL just before a migration and then waiting hours for old answers to expire.
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· follow one of these
- CourseFreeLinux Upskill Challenge
Linux Upskill Challenge · Beginner
Free, one task a day on a real cloud server: the shell skills this roadmap assumes
- VideoFreeComputer Networking: A Top-Down Approach (Video Lectures)
Jim Kurose and Keith Ross · Intermediate
Free lectures: watch the chapters on the application, transport and network layers for IP, TCP, UDP and DNS