SPF Policy controls what happens with unauthorised senders in your email domain, and it has a variety of parameters to choose from, along with 3 levels of restriction.
- “+all”: unauthorised senders are not restricted, anyone can send (not recommended).
- “~all”: unauthorised senders are allowed but monitored.
- “-all”: unauthorised senders are strictly rejected for security.
The recommended level is always “-all” to limit to your selection only, since many email services have no security restrictions for creating email accounts.