A catch-all mailbox receives emails sent to inactive addresses under the very same domain. For example, an email message sent to the misspelled firstname.lastname@example.org will be delivered to email@example.com if the catch-all feature has been activated for the latter. In this way, you can get email messages from pals or customers who may have sent a message to your email address with a spelling mistake or to an outdated one, which they may still have, but you have already deleted. Just one mailbox per domain name can be a catch-all one and email forwarding cannot be enabled for such a mailbox. The latter is due to the fact that at a certain point you may start receiving spam messages in the catch-all mailbox and the forwarding restriction implies that the spam will not be received in a 3rd-party mailbox.