Maps the domain to the DNS server. Done by Domain Registration.
Maps the domain to an IP adress. Managed by the operator of the DNS server. Correct DNS configured Servers are Registered with ARIN to offer reverse delegation. i.e reverse records that are valid. Offers various records compromising of a zone file.
Responds to the DNS records provided, on a configured Server and points to webserver / mailserver etc.
All of the following make up a record.
AAAA Record / A Record
Before going further into the details, it’s important to know that A and CNAME records are standard DNS records.
The general rule is:
use an A record if you manage what IP addresses are assigned to a particular machine or if the IP are fixed (this is the most common case) use a CNAME record if you want to alias a name to another name, and you don’t need other records (such as MX records for emails) for the same name