What Is an A Record? DNS A Record Explained

An A record, short for address record, maps a hostname to an IPv4 address. When someone looks up example.com, the A record tells their resolver which IPv4 address should answer for that name.

It is one of the most common DNS record types because it is the simplest way to point a domain or subdomain at a server, load balancer, firewall, or other service with a public IPv4 address.

If the A record is wrong, missing, or cached with an old value, users may reach the wrong server or fail to connect at all.

example.com. 300 IN A 203.0.113.10

In this example, the hostname example.com resolves to the IPv4 address 203.0.113.10 with a TTL of 300 seconds. The TTL tells recursive resolvers how long they can cache the answer before requesting it again.

• Pointing a website root domain to a web server or reverse proxy
• Publishing subdomains such as app.example.com or api.example.com
• Directing traffic to a firewall or load balancer front end
• Supporting monitoring, custom service endpoints, or legacy IPv4-only applications

Many modern services combine A records with CDN, proxy, or load-balancing features, but the underlying goal is still the same: map a hostname to a routable IPv4 destination.

• A record: maps a hostname to an IPv4 address
• AAAA record: maps a hostname to an IPv6 address
• CNAME record: aliases one hostname to another hostname
• MX record: identifies mail servers for a domain
• TXT record: publishes text data used for verification or email security

A record changes are often confused with CNAME changes. The practical difference is that an A record returns an IP address directly, while a CNAME points to another hostname that must then be resolved.

• The record points to an outdated IPv4 address after a migration
• The hostname is missing entirely, so clients receive NXDOMAIN or no answer
• The record exists on the authoritative server but public resolvers still return an older cached value
• Multiple A records exist unintentionally, causing traffic to be spread across servers that are not meant to share requests
• The domain is using a proxy or CDN and the visible address does not match the origin server

When troubleshooting, always separate authoritative DNS from resolver cache behaviour. A record changes can look inconsistent globally even when the zone itself has already been updated correctly.

dig example.com A

dig @1.1.1.1 example.com A

dig @8.8.8.8 example.com A

Start by querying the record from a couple of public resolvers. If answers differ, compare them with the authoritative nameserver response to confirm whether the change is still propagating or whether the zone is actually incorrect.

• What is DNS?
• How to Check DNS Propagation
• What Is a CNAME Record?

If you want to validate this topic in practice, these DNS Pro tools are the fastest next step.

• Record Lookup
• DNS Propagation Checker
• Domain DNS Summary