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