An A record is a DNS record that points a domain or subdomain at a server's IPv4 address.
An A record (the "A" stands for address) is the most basic entry in DNS. It tells the internet which server a name lives on by linking that name to an IPv4 address, such as 203.0.113.10. When someone types example.com into a browser, their device asks DNS for the A record, gets the IP address back, and connects to that server.
Every website needs at least one A record, or a record that ends up at one. You'll usually have one for the bare domain (example.com, often shown as "@") and either another A record or a CNAME for www.
How an A record works
An A record has a few simple parts:
- Name (host): the domain or subdomain it applies to, such as @, www or shop.
- Value: the IPv4 address of the server.
- TTL: how many seconds other servers may cache the answer before asking again.
A record lookups happen in milliseconds. Your browser asks a resolver, the resolver finds the domain's authoritative nameservers, and those nameservers return the address from the domain's zone file.
A record vs CNAME vs AAAA
These three are easy to mix up:
- An A record maps a name to an IPv4 address.
- An AAAA record does the same job for an IPv6 address.
- A CNAME maps a name to another name, which then has its own A record.
Use an A record when you know the server's IP. Use a CNAME when a third-party service gives you a hostname to point at and may change its IP addresses later. You can't put a CNAME on the bare domain alongside other records, which is why the root of a domain almost always uses an A record.
When you'd change your A record
You edit the A record when your website moves to a new server. A common case is keeping your domain at one registrar while hosting the site somewhere else: rather than changing nameservers, you just update the A records for @ and www to the new host's IP. Your email and other records stay untouched.
Before a move, it helps to lower the TTL to a few minutes a day ahead. That way, when you switch the A record, visitors pick up the new address quickly.
Common A record problems
- Old IP left behind: the site still loads from the old host because one record (often www) was missed.
- Editing the wrong DNS: if your domain uses another provider's nameservers, changes made anywhere else have no effect.
- Caching delays: resolvers keep the old answer until the TTL runs out, so changes can take a few hours to show everywhere.
- Duplicate records: two A records for the same name with different IPs send visitors to both servers at random.
You can check what a domain's A record currently returns with any DNS lookup tool, or with dig example.com A in a terminal. AblePage includes free DNS management, so you can edit A records in a couple of clicks.