Build Your Own DNS Server
Build a DNS resolver and authoritative server from scratch. You'll parse the DNS wire format, encode names with compression, handle all major record types, do CNAME chasing, perform iterative resolution from the root, and implement TTL-based caching. By the end you'll deeply understand how BIND, Unbound, dnsmasq, and AWS Route 53 actually work.
intermediate13 lessons4 chapters13 graded exercisesPython
No sign-up needed for lesson 1 · certificate on completion · sign up to save progress
What you’ll have built
Chapter by chapter. Every step is a graded exercise.
- DNS Wire Format
- Record Types & Lookups
- Recursive Resolution
- Caching & Production
Starts in Python — solve in the language you choose in the editor, same tests either way.
Curriculum
4 chapters, 13 lessons. Each lesson is a short read, one graded exercise, and a quiz.
- 1The DNS Header (12 bytes)Read · exercise · quiz
- 2Encoded Names & CompressionRead · exercise · quiz
- 3Question SectionRead · exercise · quiz
- 4Name Compression DecoderRead · exercise · quiz
Loading reference solution…