Sender Policy Framework (SPF) Records are used for email validation to mitigate spam. An SPF record is a type of Domain Name Service (DNS) record that identifies which mail servers are permitted to send email on behalf of your domain.
We recommend that you create a Sender Policy Framework (SPF) record for your domain. The purpose of an SPF record is to prevent spammers from sending messages with forged From addresses at your domain. Recipients can refer to the SPF record to determine whether a message purporting to be from your domain comes from an authorized mail server.
If your domain does not have an SPF record, some recipient domains may reject messages from your users because they cannot validate that the messages come from an authorized mail server.
SPF records can be generated using a free online tool from Microsoft