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An ALIAS record points a name at another hostname the way a CNAME does, but returns A and AAAA answers to clients instead of a CNAME. That makes it usable at the zone apex, where standard DNS forbids a CNAME. Different providers use different names for the same idea:
  • Cloudflare usually calls it CNAME flattening.
  • Other providers call it ALIAS, ANAME, or a flattened CNAME.

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When to use an ALIAS record

Use ALIAS when you want “point this name at that hostname” behavior but you can’t or shouldn’t use a CNAME. Most commonly:
  • At the zone apex (example.com), where standard DNS rules don’t allow a CNAME.
  • When you’re targeting a hostname whose addresses change — a CDN or a hosted service — but clients need to receive A and AAAA records.
A Datum Application Load Balancer endpoint is a typical target. See DNS setup for an Application Load Balancer.

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Name and value

Name — the hostname inside the zone you’re creating the record for.
  • For the zone apex, use @, the zone-file notation for the zone root.
  • For a subdomain, use the label: www for www.example.com.
Value — a target hostname, such as myapp.hosting-provider.com.
  • ALIAS values are hostnames, not IP addresses.
  • The target must ultimately resolve to A or AAAA records, directly or through further DNS indirection.
  • End the target with a dot. Without one it’s treated as relative to your zone. See Write values.

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How it works

ALIAS isn’t a standardized DNS record type that recursive resolvers understand. The authoritative nameserver does the work instead:
  1. A client’s resolver asks for A or AAAA for the ALIAS name, for example example.com.
  2. Datum resolves the ALIAS target — myapp.hosting-provider.com — to its current A and AAAA records.
  3. Datum returns those answers as if they’d been configured directly on the ALIAS name.
The consequence worth remembering: clients don’t see a CNAME in the response. They see A and AAAA records for the name they asked about.

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ALIAS compared with CNAME

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Limitations

  • Portability. ALIAS and flattening behavior isn’t uniform across providers. If you move DNS elsewhere, you’ll need to translate the record into whatever that provider supports — and a BIND zone file can’t carry it, because ALIAS isn’t a standard type. See Migrate a zone.
  • Answer types. ALIAS synthesizes A and AAAA answers. It isn’t a general replacement for other record types, and it doesn’t carry the target’s MX, TXT, or other records over to your name.
Last modified on August 26, 2026