Authenticating the sender of a message is very important as it allows you to identify legitimate messages from any spam that could use your domain, and proves to your recipients that the messages you send them are legitimate.

Proper authentication also ensures you a good sender reputation, which will help improve your delivery rate, reduce the risk of having your messages filtered and reported as spam, and improve your clients’ trust in your electronic communications.

Inversely, if your messages are not authenticated, you exposed yourself to risks. If the destination server cannot prove that the server is entitled to send messages on your behalf, then the following consequences might arise:

  • It will be more difficult to gain, and maintain, a good sender reputation, and your reputation can be easily damaged by a spam campaign that would aim at the reputation of your domain;
  • Your recipients  could be informed that the “messages don’t seem to come from your domains”, or that the source of the message cannot be confirmed;
  • Your domains could easily be used for phishing campaigns since it’s not possible to distinguish legitimate from illegitimate messages.

There are two ways to authenticate messages:

You must know that even if the DKIM signature and the SPF protocol help to prove that a message is legitimate, their absence does not however prove that they are not legitimate. It is therefore important to implement a DMARC policy to make up for this uncertainty and indicate precisely how to process messages that are not authenticated.

To learn more about the various configurations to perform when a new account is opened, read the linked articles, as well as the Complete Initial Account Configuration Guide.