DNS stands for Domain Name System. The main function of DNS is to translate domain names into IP Addresses, which computers can understand. It also provides a list of mail servers which accept Emails for each domain name. Each domain name in DNS will nominate a set of name servers to be authoritative for its DNS records.
This is where all other name servers will be pointed when looking for information about the domain name. Name servers are a program or computer server that implements a name-service protocol. This is where the zone file is stored and your DNS records are stored within. A zone file is a small set of instructions that points domain names to IP addresses.
A zone file is made up of ‘records’ such as A Records and MX Records. This record is used to point your domain name to an IP address. If you need to set up a A record, your provider would provide you with an IP address that will look something like 18.104.22.168. If you need to set up a CNAME record, your provider would provide you with a URL address that will look something like web.me.com. This is used to specify which mail servers are responsible for a particular domain name.
One special MX Record feature is priority numbers, which provide information to the querying mail server about which mail server should be used first. The next entry is tried only when the mail server with the highest priority is not available.