DKIM, which is an abbreviation for DomainKeys Identified Mail, is an email authentication system, which prevents email headers from being forged and email content from being meddled with. This is done by attaching an e-signature to every message sent from an address under a certain domain. The signature is issued on the basis of a private key that’s available on the SMTP server and it can be validated using a public key, which is available in the global DNS database. In this way, any email with altered content or a spoofed sender can be recognized by mail service providers. This approach will heighten your online security noticeably and you will know for sure that any email sent from a business partner, a banking institution, etc., is authentic. When you send email messages, the recipient will also know for sure that you are indeed the one who has sent them. Any email that appears to be fake may either be flagged as such or may never reach the recipient’s inbox, depending on how the given provider has chosen to deal with such emails.