What are DNS records ?
DNS (Domain Name System) is the Internet’s phone book. It uses the IP address as a phone number, and domains as contact names. Domain information is stored on DNS servers. To add this information to the DNS system, you need to set up resource records. With their help, servers share domain information with other servers. As long as the resource records for the domain are not registered, it is not in the “phone book” of the Internet. Therefore, the operation of the site or mail on it is impossible. Before you start specifying resource records, you need to delegate the domain, that is, register DNS servers for it. There are exist the following key resource records types: A, CNAME, MX, TXT, and SPF records.
The A (address) entry is one of the key DNS records. It is needed to connect the domain with the server IP address. Until the A-record is registered, your site will not work. When you enter the name of the site in the address bar of the browser, it is by the A-record that the DNS determines which server to open your site from. .
CNAME (Canonical name) – a record that is responsible for binding subdomains (for example, app.sitechecker.pro) to the canonical domain name (sitechecker.pro) or another domain. The main function of CNAME is to duplicate domain resource records (A, MX, TXT) for various subdomains.
This is the record responsible for the server through which mail will work. MX records are critical to mail. Thanks to them, the sending party “understands” which server to send mail to for your domain.