Networking · 5 min read

Understanding DNS Records

A clear guide to DNS and its record types — A, AAAA, MX, TXT, NS, CNAME — and how domain names get resolved to IP addresses.

The Domain Name System (DNS) is the internet's phone book. When you type example.com, DNS translates that human-friendly name into the IP address a browser needs to connect. The lookup travels from your resolver to the domain's authoritative name servers, which return the answer.

Common DNS record types

  • A — maps a domain to an IPv4 address.
  • AAAA — maps a domain to an IPv6 address.
  • MX — mail exchange; tells senders which servers accept email for the domain (with priorities).
  • TXT — arbitrary text, widely used for SPF, DKIM, and domain verification.
  • NS — the authoritative name servers for the domain.
  • CNAME — an alias pointing one name to another.

Why DNS changes take time

Each record has a TTL (time to live) that tells resolvers how long to cache it. After you change a record, older cached values can persist until the TTL expires — this is why DNS updates can take minutes to hours to "propagate."

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