What is the difference between an A record and a CNAME?

An A record maps a hostname directly to an IPv4 address. A CNAME aliases one hostname to another name, which is then resolved. A CNAME cannot coexist with other records at the same name and is not allowed at the zone apex.

Which record type is used for email?

MX records specify the mail servers for a domain, each with a priority value where a lower number is preferred. SPF, DKIM and DMARC policies are published as TXT records.

What is the difference between A and AAAA records?

An A record points a hostname to an IPv4 address (like 93.184.216.34), while an AAAA record points it to an IPv6 address (like 2606:2800:220:1::1946). Domains often have both so they work over either protocol.

What is a TXT record used for?

A TXT record holds arbitrary text and is widely used for email authentication (SPF, DKIM, DMARC) and for verifying domain ownership with services like Google or Microsoft. SPF is published as a TXT record rather than the deprecated SPF type.

Why can't I put a CNAME at the root domain?

The zone apex (the bare domain like example.com) must carry SOA and NS records, and a CNAME cannot coexist with other records at the same name. Providers offer ALIAS or ANAME records to get CNAME-like behaviour at the apex.

What are CAA records for?

A CAA record lists which certificate authorities are allowed to issue TLS certificates for your domain, for example 'issue letsencrypt.org'. It is a safeguard against unauthorised certificate issuance.

Is any data sent anywhere?

No — this is a static reference that runs entirely in your browser. Nothing is uploaded.

What is the DNS Record Types Reference?

A searchable reference of DNS record types — A, AAAA, CNAME, MX, TXT, NS, SOA, CAA, SRV and more — with plain-English meanings and zone-file examples. Runs entirely in your browser. It runs free in your browser on Gera Tools, with nothing uploaded.

DNS Record Types Reference

Name: DNS Record Types Reference
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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DNS record types reference

A searchable reference of the DNS record types you work with most, from A and AAAA to CNAME, MX, TXT, NS, SOA, CAA, SRV and the DNSSEC records. It is for developers and site owners setting up domains, email and certificates who need to pick the right record quickly.

How it works

DNS translates human-friendly names into the addresses and metadata that make the internet work, and each record type does a specific job. Type a record type or keyword — for example CNAME, mail or dnssec — and the list filters instantly by type name, full name or description. Each entry shows a plain-English meaning and a sample zone-file line you can adapt. The reference is static and runs entirely in your browser.

Quick reference

Type	Purpose	Example data
A	Hostname → IPv4 address	93.184.216.34
AAAA	Hostname → IPv6 address	2606:2800:220:1::1946
CNAME	Alias one name to another	example.com.
MX	Mail server + priority	10 mail.example.com.
TXT	Free text (SPF, DKIM, verification)	“v=spf1 ~all”
NS	Delegate zone to name servers	ns1.example.com.
SOA	Zone metadata and timers	ns1… admin… serial…
CAA	Allowed certificate authorities	0 issue “letsencrypt.org”
SRV	Service location + port	10 20 5060 sip.example.com.
PTR	Reverse DNS — IP → hostname	host.example.com.

Choosing the right record

Setting up a website — point www at your host with a CNAME (if pointing to another hostname) or an A/AAAA record (if pointing to an IP). For the bare domain (example.com without www), a CNAME is not allowed at the zone apex; use an A record or your registrar’s ALIAS/ANAME feature if the host provides a hostname instead of an IP.

Routing email — you need at minimum an MX record and an SPF TXT record. Add DKIM (TXT at selector._domainkey.domain) and a DMARC policy (TXT at _dmarc.domain) for deliverability and spoofing protection.

Adding a subdomain — a CNAME pointing app.example.com to a CDN or PaaS hostname is the usual approach. Remember: if you have other records at that exact name (for example a TXT for verification), a CNAME cannot coexist with them at the same label.

Restricting certificate issuance — a CAA record with 0 issue "letsencrypt.org" permits only Let’s Encrypt to issue for your domain. Add a line for each authority you use; an empty CAA set means any CA can issue.

Zone-file format reminder

Every record follows the pattern name [TTL] [class] type rdata. The class is almost always IN and is often omitted. A trailing dot after a hostname marks it as fully qualified (absolute) rather than relative to the zone origin. Omitting the dot at the end of a CNAME target is a common mistake that appends the zone name to the target.

; A record
www.example.com.   3600  IN  A     93.184.216.34

; MX record with two priorities
example.com.       3600  IN  MX    10 mail1.example.com.
example.com.       3600  IN  MX    20 mail2.example.com.

; SPF TXT record
example.com.       3600  IN  TXT   "v=spf1 include:sendgrid.net ~all"

Everything runs in your browser — nothing is uploaded.