Beamfar
Sign inStart the 14-day trial

What is a DNS record?

Last updated .

A DNS record is a single entry in a domain’s DNS zone. Each has a name, a type, a value and a TTL. The zone is the full set of records for the domain, held by its name servers.

Definition
DNS record
One entry in a domain’s DNS zone that maps a name to data, such as an IP address (A, AAAA), an alias (CNAME) or mail servers (MX).

Common types

  • A and AAAA: map a name to an IPv4 or IPv6 address, which is how a browser finds the server.
  • CNAME: makes a name an alias of another name.
  • MX: names the servers that accept email, with priorities.
  • TXT: free text, used for ownership verification and email authentication such as SPF, DKIM and DMARC.
  • NS: names the authoritative name servers.
  • CAA: restricts which certificate authorities may issue certificates for the domain.
  • SOA: describes the zone itself.

Why records break sites

A zone mixes the website’s records with those of mail, verification and third-party services. Deleting a record you did not read, leaving an old address beside a new one, or moving name servers without copying the zone are the common causes of outages.

An example zone

example.com.      3600 IN A     203.0.113.10
www.example.com.  3600 IN CNAME example.com.
example.com.      3600 IN MX    10 mail.example.net.
example.com.      3600 IN TXT   "v=spf1 include:_spf.example.net -all"

Four records, four jobs: the web address, an alias, mail routing and mail authentication. dig example.com MX +short shows one type. Ask the authoritative server directly with dig @ns1.example.net example.com A to see what the zone really holds, without a resolver’s cache in between.

What to check

An export of the zone before every change, the values served by the authoritative nameserver afterwards, and a record of who changed what.

Sources

Read on . Standards and vendor pages change; confirm the current text before you rely on it.

Guides that use this term

  • TTLTTL is the number of seconds a DNS answer may be cached. How it makes DNS changes spread slowly, how to lower it before a change and why it is a maximum, not a promise.
  • CNAMEA CNAME record makes one name an alias of another. Why a name with a CNAME cannot hold other records, which blocks it from the root of a domain.
  • NameserverA nameserver is the server that holds a domain’s DNS records and answers queries for them. Why moving nameservers moves the whole zone and what to copy first.
  • MX recordAn MX record lists the mail servers for a domain with priorities. What happens to email when it is missing or points to the wrong provider.

Know first. Know why. Tell your client before they call.

Paste your client list. Both regions start checking.

Start the 14-day trialWhat Beamfar watches

No card for the trial.