Start

The DNS wiki

Every page, by section. New to DNS? start-here for the guided path; the sections below run roughly beginner to advanced.

Broken right now? Start with troubleshooting and work down.

Asks the demo zone for an address, which every page here builds on.

$ dig @1.1.1.1 example.isitdns.net A

; <<>> DiG 9.20.11-0ubuntu0.2-Ubuntu <<>> @1.1.1.1 example.isitdns.net A

; (1 server found)

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status:

NOERRORThe server had no complaint about the question.

, id: 36864

;; flags:

qrThis message is the answer coming back, not the question going out.

rdYou asked this server to go and find the answer for you.

raThis server says it is willing to go and find answers for you.

adThis server says it checked the signatures, and they held up.

; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:

; EDNS: version: 0, flags:; udp: 1232

;; QUESTION SECTION:

;example.isitdns.net. IN

AYou asked for the IPv4 address this name points at.

;; ANSWER SECTION:

example.isitdns.net.

300How many seconds this answer can be reused before asking again. From a cache it is the time left, so it counts down.

IN A 192.0.2.1

;;

Query timeHow long this one lookup took, start to finish.

: 35 msec

;; SERVER: 1.1.1.1#53(1.1.1.1) (UDP)

;; WHEN: Mon Sep 14 17:42:30 CDT 2026

;; MSG SIZE rcvd: 64

good: NOERROR, one A record, 192.0.2.1

bad: SERVFAIL, or any address that is not 192.0.2.1

run this query in the dig tool →

Foundations#

fundamentals · anatomy-of-a-query · query-types · foundations-osi

Records#

Records overview · a · aaaa · cname · mx · ns · ptr · soa · txt · srv · caa · https-svcb · sshfp · tlsa · email-records

Tools#

dig-tool · dig-along · dig-examples · dig-flags · nslookup-and-dig · dig-phonebook · ask-dns · when-its-dns · tldr-dnssec · dnssec-viz

Troubleshooting#

Start here · check-a-resolver · check-a-forwarder · check-a-delegation · check-an-auth

Zones#

Zones overview · auth · forward · delegations · stub · transfer

Security and integrity#

dnssec · dnssec-troubleshooting · ksk-roll-2026 · ksk-roll-2026-reference · extended-dns-errors · dnsviz · dot-doh · caa-policy · ddns · split-horizon · cloudflare-hardening

Reference#

glossary · rfc-index · record-types · reverse-dns · wireshark-dns-filters

It was DNS. It is always DNS.