A Record
DNSA Record is a DNS resource record that maps a hostname (such as example.com or www.example.com) to an IPv4 address. When a browser or app looks up a domain, resolvers use the A record to find the server to connect to. It is foundational for pointing domains to web servers, load balancers, or other internet-facing services using IPv4.
How It Works
An A record lives in a domain's DNS zone and answers the question: which IPv4 address should this name resolve to? When a user enters a domain, a recursive resolver queries authoritative name servers for the zone. If an A record exists for the requested hostname, the authoritative server returns the IPv4 address, and the client connects to that address on the appropriate port (typically 80/443 for web traffic).
A records can be set at the apex (the root domain) and for subdomains. They also include a TTL (time to live) value that controls how long resolvers cache the answer before rechecking, affecting how quickly changes propagate. Multiple A records can be published for the same hostname to support basic load distribution or redundancy, and they are often paired with other records like CNAME, AAAA (IPv6), and MX depending on the services attached to the domain.
Why It Matters for Web Hosting
When you buy hosting, the A record is one of the main ways you point your domain to the hosting environment. If you move to a new server, switch to a reverse proxy, or place a CDN or load balancer in front of your site, you typically update the A record to the new IPv4 address. Understanding TTL, apex support, and multi-record behavior helps you plan migrations, reduce downtime, and choose DNS and hosting setups that fit your reliability needs.
Common Use Cases
- Pointing the root domain (example.com) to a web server IPv4 address
- Pointing a subdomain (app.example.com) to an application server or API endpoint
- Directing traffic to a load balancer or reverse proxy that fronts multiple servers
- Publishing multiple A records for redundancy or simple round-robin distribution
- Updating DNS during a hosting migration to a new IPv4 address
A Record vs CNAME Record
An A record maps a name directly to an IPv4 address, while a CNAME maps a name to another hostname (which then resolves via its own A/AAAA records). A records are commonly used at the root domain because many DNS providers restrict CNAME usage at the apex, whereas CNAMEs are convenient for subdomains when you want the target to follow another hostname that may change its underlying IPs.