Check DNS A Records

An A record is a DNS record that maps a domain name to an IPv4 IP address. For example, the www.dnscheck.co A record maps to the 104.131.72.189 IP address. The IPv6 equivalent of an A record is a AAAA (quad A) record.

A records are also be referred to as "address records" and "host records", and are defined in RFC 1035.

DNS Check can monitor your A records, and notify you if they become unresolvable, or start resolving to the wrong IP address.

Fields

Here are the fields that make up an A record:

Field	Description	Example
Name	A fully qualified domain name (FQDN).	www.dnscheck.co.
Type	The DNS record type. Always set to "A".	A
Address	An IPv4 IP address.	104.131.72.189

DNS Zone File Examples

Here's an example of how an A record looks in a DNS zone file:

; Name           Type  Address
www.dnscheck.co. A     104.131.72.189

The Name ends in a period in the above example, so it's a fully qualified domain name.

Alternatively, you can create an A record that's relative to the zone file's $ORIGIN. Here's an example of how to use this technique to define the same record as in the previous example:

$ORIGIN dnscheck.co.
; Name           Type  Address
www              A     104.131.72.189

Additional Resources

• RFC 1035 - section 3.4.1 (A RDATA format) defines the format that A records follow.