DomainKeys Identified Mail, or DKIM, is a system for verifying the legitimacy of an email message using an e-signature. When DKIM is activated for a specific domain name, a public cryptographic key is published to the global DNS database and a private one is kept on the email server. If a new email message is sent, a signature is issued using the private key and when the message is delivered, that signature is checked by the incoming POP3/IMAP email server using the public key. Thus, the receiver can easily know if the email is authentic or if the sender’s address has been spoofed. A discrepancy will occur if the content of the email has been modified on its way as well, so DKIM can also be used to make sure that the sent and the received messages are identical and that nothing has been added or removed. This validation system will strengthen your email security, since you can verify the authenticity of the important emails that you get and your colleagues can do the exact same thing with the emails that you send them. Depending on the given email service provider’s policies, an email message that fails to pass the examination may be erased or may end up in the receiver’s inbox with a warning notification.


The SMTP acronym stands for Simple Mail Transfer Protocol and this is the set of scripts that allows you to send out emails. If you work with an email application, it creates a connection to the SMTP server. The latter then searches the DNS data of the domain name, which is a part of the receiving address to find out what email server handles its emails. After system information is transferred, the SMTP server provides the email to the remote IMAP or POP server and then the email is finally delivered in the corresponding mailbox. An SMTP server is necessary if you are using a contact page form on your website too.