DNS records explained: A, AAAA, CNAME, MX, TXT, NS and more
A plain-English reference to every DNS record type that matters — what each does, when to use it, and the mistakes that take sites and email offline.
DNS is the phone book of the internet: it turns a name people remember (example.com) into the addresses and services machines need. Your DNS zone is a set of records, each a small instruction. Here's what each type does and how not to break your site or mail.
Records that point to your website#
| Type | Purpose | Example value |
|---|---|---|
| A | Maps a name to an IPv4 address | 203.0.113.10 |
| AAAA | Maps a name to an IPv6 address | 2606:4700::1 |
| CNAME | Aliases one name to another name | cdn.provider.net |
Records that route and protect email#
- MX — your mail servers, each with a priority (lower = tried first).
- TXT — free-form text, used for SPF, DKIM, DMARC and domain verification.
- No MX record means the domain can't receive mail. SPF/DKIM/DMARC are all TXT records — see the deliverability guide.
Infrastructure & control records#
| Type | Purpose |
|---|---|
| NS | Which nameservers are authoritative for the zone |
| SOA | Zone metadata (primary NS, serial, refresh timers) |
| CAA | Which certificate authorities may issue certs for you |
| PTR | Reverse DNS — IP back to a hostname (set at your IP provider) |
| SRV | Locates a service (host + port), e.g. for VoIP/chat |
| HTTPS/SVCB | Modern record advertising HTTPS/HTTP-3 endpoints |
- Run at least two nameservers for redundancy.
- Add a CAA record to reduce mis-issuance risk.
TTL and propagation#
Every record has a TTL (time to live) — how long resolvers cache it. Before a planned change, lower the TTL (e.g. to 300s) a day ahead so the change 'propagates' quickly; raise it back afterwards for efficiency. 'DNS propagation' is just caches expiring.
Inspect any domain's full record set — plus SPF/DMARC parsing and DNSSEC — with the DNS Lookup tool.
Frequently asked questions
▸ ▾ What's the difference between an A record and a CNAME?
An A record points a name directly at an IP address. A CNAME points a name at another name (an alias), which is then resolved to an IP. Use A/AAAA for the apex and where you need other records on the same name; CNAME for subdomains that follow a provider's hostname.
▸ ▾ Why can't I put a CNAME on my root domain?
The DNS spec doesn't allow a CNAME to coexist with other record types on the same name, and the apex needs SOA/NS (and usually MX/TXT). Use an A/AAAA record, or your DNS provider's ALIAS/ANAME flattening feature, at the apex.
▸ ▾ How long does DNS propagation take?
It's caches expiring, governed by each record's TTL. With a low TTL (e.g. 300s) changes appear within minutes; with a high TTL (e.g. 86400s) they can take up to a day. Lower the TTL before a planned change.
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Published 2026-07-09 · Updated 2026-07-09 · By Crawlsonar.