Dictionary · Protocols and Ports
DNS
DNS — Domain Name System
Name services · Beginner
A distributed directory that translates human-readable names into addresses and other records. Resolvers cache answers, and authority for a name is delegated through a hierarchy.
People type names. Computers need numbers. This system publishes those mappings and lets a resolver walk the hierarchy until it finds an answer it is allowed to trust.
Picture it
People type names. The resolver follows referrals from the root to the name's authority, then caches the answer for the stated time to live. This system publishes mappings. It does not lease a device its address.
Example: A resolver asks for the address record of example.com and caches the answer for the stated time to live.
Ports
- UDP 53 — Ordinary queries
- TCP 53 — Large responses and zone transfers
Common misconception
- It does not assign a device its own address. A configuration lease does that. This system publishes how to look a name up.