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NET-C0039 · DNS Tools

DNS Record Types Explained

Name the record type you mean, and look up only a name you administer or were asked to read.

Updated 25 October 2026 · Explainer

This is an original planning guide. It is not a vendor manual, an official standard, or legal advice. Example addresses use documentation ranges. Review every command before you paste it.

What this hour is for

An A record maps a name to IPv4. AAAA maps to IPv6. CNAME is an alias. NS delegates. TXT carries text such as a policy another team owns. MX is mail, and it has its own page.

The lookup tools ask the DNS for a name you type. Use a name in a zone you operate, or a name a ticket told you to read. Do not walk a zone you do not run. Do not request a zone transfer.

A CNAME at the zone apex, or a CNAME beside other records at the same name, is a mistake you can see if you list the name. The SPF companion on the security desk owns mail policy text. This page only tells the types apart.

TTL is part of the record. A change you publish will be remembered for that long. Write the TTL before you change anything. This page does not change the zone.

The change you can finish

Apply nothing during the writing of the note. When the lab window opens, it is one change on the device named in the ticket. Read the draft, then the device, then decide.

Rollback is the file or the revision you saved first. You do not invent a rollback after the only copy is gone.

  1. Pick one name you may query.
  2. Look up one type.
  3. Write the answer and the TTL.
  4. If the type is not the one you needed, look up that type next, not every type.
  5. Do not request a transfer.
  6. Hand a change to the zone's own change window.

Mistakes that outlive the command

DNS Record Types Explained goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.

Decisions to write down

One decision for DNS Record Types Explained: The name is one you may query. One type was looked up. TTL was written. No transfer was requested. And no zone was edited.

Checks before you call it done

Confirm this before you call the change done: The name and type are in the ticket. The answer matches what you expected or the exception is written. TTL is recorded. No AXFR was attempted. And the zone is unchanged. If one of those fails, stop.

One name. One type. No zone transfer.
example.com is documentation.

Before you leave the device

DNS Record Types Explained ends when the hostname on the device matches the hostname in the ticket. If it does not, you are on the wrong box. Stop. A command that succeeded on the wrong box is not progress.

The draft stays a draft until a person has read the names in it. A generator does not log into the device and does not know which interface is the uplink. You delete a line that names a device, a zone, or a prefix you did not write down.

0.0.0.0/0 is not kept because a sample included it. A source you can say is the source you keep. 192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. They belong in the note. They are not prefixes you type onto a production device because they appeared in a draft.

prompt-for-this is a reminder that a secret is missing. It is not a password, a key, a community string, or a pre-shared key you save in the ticket or in git. The real secret stays in the store.

One change is the window. A VLAN and a routing protocol and a VPN do not share it. If two things move and the result is wrong, you will not know which one did it. The next feature waits for its own page.

If the same step fails twice, stop for the day. The failure is the result. Adding a forum command beside a half-applied config produces a device nobody can rebuild. Restore the copy you took first.

A second person reads the device name and the change aloud. If they cannot find them in the ticket, the note is not done. Silence is not agreement. Then leave the device alone.

This page is a planning guide. It is not a vendor manual, not an official standard, and not a permission to touch a network you do not administer. The pillar guide owns the wider design. This page owns one lab proof.

Tools for this guide

These tools run in the browser on this site. They do not log into your machines.

More in this cluster

The pillar for this page, and the next published pages filed with it.

Companion: Security: SPF Record Generator & Checker.