A catch-all mailbox receives email messages sent to non-existent email addresses under the same domain. For instance, an email sent to the mistyped firstname.lastname@example.org will go to email@example.com if the catch-all feature has been activated for the latter. In this way, you can receive emails from colleagues or customers who may have sent a message to your email address with a spelling mistake or to an old one, which they may still have, but you have already disabled. Only one mailbox per domain name can be a catch-all one and email forwarding cannot be enabled for such a mailbox. This is so because of the fact that at a certain moment you may start receiving spam messages in the catch-all mailbox and the forwarding restriction means that the spam will not be sent to a third-party mailbox.