A record

An A record maps a hostname to an IPv4 address. For example, www.example.it may have an A record pointing to the web server's IPv4 address. When a browser accesses that name, the resolver checks its cache or queries DNS hierarchy. The A record does not contain the website or register domain ownership; it only provides data needed to locate the service. It is among the most recognized DNS records because it links human-readable names to responding servers.

Name, Zone, and Value

Each record has a name, type, value, and TTL, plus other DNS-managed parameters. The name can be the main domain like example.it or subdomains such as www.example.it. An A record's value must be an IPv4 address in four-component format. TTL defines how long resolvers cache responses before requerying. It does not determine record expiration or replace registration renewal.

Multiple A records for the same name support load distribution across multiple addresses or redundant infrastructure. The resolver or client selection process depends on contextual requirements and specific service needs. An A record may be published alongside other DNS record types including AAAA for IPv6 addressing, MX for email services, TXT for verification and authentication purposes, and CNAME for aliasing, while adhering to applicable DNS regulations. A consistent configuration must account for all services utilizing the zone, rather than focusing solely on the homepage.

What It Does and What It Doesn’t

A records primarily make websites, APIs, dashboards, and IPv4 services reachable. Changing the value shifts traffic to a new server or provider but does not copy files, databases, certificates, emails, or configs. Before changing, ensure the destination is ready with correct virtual host and certificate. If only DNS changes without updating the service, resolution may succeed but show errors or wrong content.

An A record is not the same as a redirect. When two domain names point to the same IP address, the server can still display different pages based on the requested name, or may fail to recognize one of the names. Redirecting visitors to another URL requires HTTP responses or forwarding services. Similarly, changing an A record does not modify the domain owner, registrar, or delegated nameservers. These represent distinct levels: registration identifies the owner, delegation indicates who manages the zone, and A records specify values within that zone.

TTL, Propagation, and Testing

After changes, users may still see old addresses until DNS caches expire. This is often called propagation, but no global switch exists—resolvers update at different times. Lowering TTL before migration reduces cache retention, but the change must be visible first. A short TTL increases queries and does not fix misconfigured zones or delegation.

Verification should query authoritative nameservers and multiple resolvers to distinguish official from cached responses. It confirms IPv4 address accuracy, record consistency, and service availability over HTTP/HTTPS. In load balancing, CDN, or DNS proxy setups, observed values may be intermediaries, not origin servers. Documenting previous value, new value, TTL, and time aids rollback. In summary, A records link DNS names to IPv4 addresses; they are essential for routing but must align with delegation, services, certificates, and migration plans.