A catch-all email mailbox receives messages sent to inactive addresses under the same domain name. For example, an email sent to the misspelled firstname.lastname@example.org will be delivered to email@example.com in case the catch-all feature has been enabled for the latter. In this way, you can receive emails from pals or clients who may have sent a message to your email address with a typographical error or to an out-of-date one, which they may still have, but you have already disabled. Only one single mailbox per domain name can be a catch-all one and email forwarding cannot be set up for such a mailbox. This is so because of the fact that at a certain point you may start receiving spam messages in the catch-all mailbox and the forwarding restriction means that the spam will not be re-sent to a third-party mailbox.