A company's application is hosted by an internet provider at app.

When mapping one domain name to another domain name that is hosted outside AWS, a CNAME record is the correct DNS record type. CNAME records map an alias name (www.company.com ) to a canonical domain name (app.example.com).

Alias records cannot be used to point to non-AWS resources. A and PTR records map IP addresses, not domain names, and are therefore not appropriate.

Because www.company.com is not the zone apex, a CNAME record is valid and supported. This solution requires no additional infrastructure and is the standard DNS approach for this scenario.