The Domain Name System(DNS) has several types of resource records that full fill the name to ip address translation(Directly or indirectly). One of the widely used record is MX Record.
An MX record should return the fully qualified domain name of an email server and its preference value .
MX Record can be configured by following the step below.
1. Open DNS Manager
2. Add A Record for your mail
(eg: mail.domain.com with the ip address of another server)
3. Add MX Record and set FQDN to the name assigned in A Record
Preference number can have any value between 0 to 65535 and lower number sets for higher priority.
After completing this step, The mail server is pointed to the ip addres provided in the A record for the specific domain.