SPF and DKIM are email authentication tools from preventing spam. SPF & DKIM attempt to equip email messages with verifiable information so that the nature of incoming and outgoing messages can be detected automatically. Enabling these features should reduce failed delivery notifications when spammer forge messages using your domain. They also prevent spammers from forging messages that claim to be from your domain.
DKIM (DomainKeys Identified Mail) is a means of verifying incoming email. It ensures that incoming messages are unmodified and from the sender from whom they claim to be. This feature works to prevent incoming spam messages.
The SPF (Sender Policy Framework) system allows you to specify servers and IP addresses that are authorized to send mail from your domain(s). This feature works to prevent outgoing spam messages.
Below are the steps to configure SPF and DKIM:
Login to your cPanel & access option Email >> Authentication. You will see the option to activate the above 2 utilities. Click on Enable & entry will be made in zone file for your domain on the server. If you are familiar with setting SPF records, you have option Advanced Settings to configure it accordingly.
DMARC is TXT record that practically asks the receiver to send an email to a particular email address, if he has received spam emails from a certain domain.
You can add this record as below:
Login to your cPanel and access the Advanced DNS Zone Editor and then add TXT record. It should appear as below:
_dmarc.domain.TLD IN TXT 14400 "v=DMARC1; p=none; rua=mailto:postmaster@your_domain.com"
Here, you need to change the domain.TLD and postmaster@your_domain.com to the correct ones as per your case.
It is also possible to use custom SPF and DKIM values for your domains. The records can be added via the DNS Zone Editor in cPanel.
In this way, you can add SPF, DKIM and DMARC records on your domain.