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It was DNS. It is always DNS.

A hands-on DNS reference where the examples actually run (unless something really is wrong with DNS). The demo records live in a real public zone, example.isitdns.net, so you can paste nearly every command on these pages into your own terminal and get the same records back. A few examples need a newer dig or kdig, and some deliberately return an error rcode instead of a record. Naturally volatile values differ run to run: TTLs count down, DNSSEC signatures rotate.

Try it:

dig @1.1.1.1 +short txt.example.isitdns.net TXT

"It was DNS. It is always DNS."

That record is real, and so are the A, AAAA, CNAME, MX, SRV, and CAA records you meet in the walkthrough. They resolve for real, but every address is a documentation address (192.0.2.1 from RFC 5737, 2001:db8::1 from RFC 3849), so nothing routes anywhere.

Two ways in#

Learn by doing: guided lessons, one query at a time:

The dig-along: every common record type, live. The best place to start.
Live examples: DNSSEC, NXDOMAIN, ECS, encrypted DNS, and ANY/RFC 8482, with annotated output.

Look something up: the reference wiki, a page for every part of DNS:

The DNS wiki: read it in order to understand DNS from the ground up, or jump straight to what you need. Records, zones, DNSSEC, DoT/DoH, the tools, and the RFC index all live here.
The dig phonebook: every dig and nslookup command in the wiki on one page, sorted by what you are trying to see.

What's inside the wiki#

Foundations: how a lookup actually works (stub to recursive to root to authoritative), recursive versus authoritative, and the query types.
Records: a page on each type (A, AAAA, CNAME, MX, NS, PTR, SOA, TXT, CAA, and more): what it holds, when to use it, a live dig, and the RFC behind it.
Zones: authoritative, forward, delegated, stub, and zone transfer.
Security: DNSSEC, DoT/DoH/DoQ, path attestation, CAA policy, and hardening.
Tools: dig and nslookup, the dig-flag reference, Wireshark filters, and "when it actually is DNS".

Throughout the wiki, claims link out to the RFC or vendor doc behind them, and the RFC index collects the RFCs, IANA registries, and official sources in one place, so this is a starting point, not the last word.