We set up MX, SPF, DKIM, DMARC and rDNS
MX (Mail Exchange) records
The MX record tells the sending mail server where to deliver the mail.
SPF (Sender Policy Framework) records
Sender Policy Framework is a record that is used to help prevent email spoofing.
DomainKeys Identified Mail (DKIM) is a method for associating a domain name to an email, thereby allowing an organization to take responsibility for a message in a way that can be validated by a recipient.