DNS

DNS translates domain names into IP addresses using a distributed lookup system.

Updated: 2026-03-05

Definition

Domain Name System (DNS) resolves names like example.com into IP addresses so clients can connect to services.

DNS uses records (A, AAAA, CNAME, MX, TXT) and caching to improve performance.

Key points

Hierarchical, distributed system
Caching reduces lookup time
DNS issues often look like 'internet is down'

Common mistakes

Forgetting TTL/caching during changes.
Ignoring DNS security (spoofing, hijacking, misconfig).

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