Securing the mails delivery

To secure your mail server and the delivery of your e-mails, we recommend that you use the following three protocols:

SPF

The Sender Policy Framework (SPF) allows to declare your mail server as authorized to originate mail for your domain(s).

To configure it, you have a single dns record to add:

Type: TXT
Host: mail.@ (depending of your DNS provider, it can be your domain name example.com, a blank string, a @, etc.)
Value: 1.2.3.4v=spf1 include:_spf.hosterra.tech ~all

DKIM