Glossary
DNS RECORDS

A Record

A DNS record that maps a hostname to an IPv4 address. The most fundamental DNS record type.

An A record (Address record) is a DNS record that maps a fully qualified domain name (FQDN) to an IPv4 address. It is the most fundamental DNS record type — when a browser resolves example.com, it is ultimately looking for an A record (or AAAA for IPv6) to find the server to connect to.

Format

example.com.      3600  IN  A  93.184.216.34
www.example.com.  3600  IN  A  93.184.216.34
api.example.com.  300   IN  A  203.0.113.42

Fields: hostname TTL class(IN) type(A) IPv4-address

Multiple A Records

Publishing multiple A records for the same hostname implements DNS round-robin — each query returns all records, typically shuffled, so clients distribute across multiple IPs:

example.com.  300  IN  A  10.0.0.1
example.com.  300  IN  A  10.0.0.2
example.com.  300  IN  A  10.0.0.3

A vs CNAME

  • A record: maps directly to an IP — can be used at the domain apex (@)
  • CNAME: maps to another hostname — cannot be used at the domain apex

Use A records for servers you control directly. Use CNAME for subdomains pointing at CDNs, SaaS platforms, or load balancers where the IP may change.

Browse every major DNS record type, check the CNAME record glossary entry, or read the nameserver definition for how A records get served.

← All terms Learning hub →