We can't stop the spammers sending the emails, but what we can do is tell the email servers around the world that the spammers weren't authorised to send those emails (most good mailservers will check, but there's a lot of badly configured mailservers out there as well which will still trigger backscatter).
- Login to your cPanel
- Go to Mail -> Email Authentication
DKIM helps verify the sender and integrity of a message. It allows an email system to prove that a message was not altered during transit (meaning it is not forged), and that the message came from the specified domain.
- To use DKIM, click Enable.
- To disable DKIM, click Disable.
This function attempts to prevent spammers from sending email while forging your domain’s name as the sender (spoofing). This authentication function works by adding IP addresses to a list, specifying computers that are authorized to send mail from your domain(s). It verifies that messages sent from your domain(s) are coming from the listed server, reducing the amount of backscatter you receive.
- To use SPF, click Enable.
- To disable SPF, click Disable.