DNS A Record: IPv4 Addresses Explained
A DNS A record maps a hostname to an IPv4 address. It is the most fundamental record in DNS: when a browser needs to reach example.com, it asks a resolver for the domain's A record and connects to the 32-bit IPv4 address it returns. The A stands for address.
What is an A record?
Defined in RFC 1035, the A record performs forward resolution for IPv4 — turning a human-readable name into the numeric address a machine can route to. Its IPv6 counterpart is the AAAA record; a host that publishes both is reachable over either protocol (a dual-stack setup).
A record structure and example
example.com. 3600 IN A 93.184.216.34| Field | Meaning |
|---|---|
| Name | The hostname the record applies to (example.com). |
| TTL | Time to live in seconds — how long resolvers cache the answer. |
| Type | Always A for IPv4 address records. |
| IPv4 address | The 32-bit destination, written as four decimal octets separated by dots. |
A single hostname can have several A records pointing to different IPs. Resolvers hand them out in rotation — a simple load-spreading technique called round-robin DNS.
How to check a domain's A record
# dig (Linux/macOS)
dig example.com A +short
# nslookup (Windows/cross-platform)
nslookup example.comTo see the A record beside every other record for a domain in one view, run it through the free DNS lookup tool.
A record vs AAAA record vs CNAME
| Record | Points to |
|---|---|
| A | An IPv4 address (e.g. 93.184.216.34). |
| AAAA | An IPv6 address. |
| CNAME | Another hostname (an alias), not an address. |
Common A record problems
- Stale record after a server move. If you migrate hosts but leave the old IP in the A record, traffic keeps hitting the dead server until DNS is updated and the old TTL expires.
- Very long TTL during a migration. A high TTL means changes propagate slowly. Lower it a day before a planned move, then raise it again afterward.
- Missing AAAA alongside A. Publishing only an A record leaves IPv6-only clients unable to reach the host.
Related DNS records
The A record is one piece of a domain's DNS. The SOA record defines the zone, NS records delegate it, MX records route its email, and PTR records provide the reverse mapping from IP back to hostname.
Frequently asked questions
What is the difference between an A record and a CNAME?
An A record points a hostname directly to an IPv4 address. A CNAME record points a hostname to another hostname, which is then resolved to an address. Use an A record for the final destination and a CNAME for aliases.
Can one hostname have multiple A records?
Yes. Multiple A records enable round-robin DNS, where resolvers rotate through the addresses to spread traffic across several servers.
Can I point an A record at a hostname?
No. An A record's value must be an IPv4 address. To point at another name, use a CNAME instead.