DomainKeys Identified Mail, or DKIM, is a system for validating the genuineness of an email by using a digital signature. When DomainKeys Identified Mail is enabled for a given domain name, a public key is published to the global DNS database and a private one is kept on the email server. If a new email is sent, a signature is generated using the private key and when the email message is received, the signature is verified by the incoming POP3/IMAP server using the public key. In this way, the recipient can easily tell if the email is authentic or if the sender’s address has been forged. A mismatch will appear if the content of the email has been modified in the meantime as well, so DKIM can also be used to make sure that the sent and the delivered messages are identical and that nothing has been attached or deleted. This validation system will enhance your email security, since you can confirm the genuineness of the important emails that you receive and your colleagues can do the same with the messages that you send them. Based on the particular email service provider’s policies, a message that fails the test may be deleted or may end up in the receiver’s inbox with a warning symbol.