A catch-all mailbox receives messages sent to inactive addresses under the exact same domain name. For instance, an email message sent to the miswritten email@example.com will be delivered to firstname.lastname@example.org if the catch-all feature has been enabled for the latter. In this way, you can receive messages from acquaintances or clients who may have sent a message to your email address with a typographical error or to an outdated one, which they may still have, but you have already deactivated. Only one single mailbox per domain can be a catch-all one and email forwarding cannot be activated for such a mailbox. This is due to the fact that at some moment you may start receiving spam messages in the catch-all mailbox and the forwarding restriction means that the spam will not be delivered to a third-party mailbox.