A catch-all mailbox receives emails sent to nonexistent addresses under the exact same domain name. For example, an email sent to the mistyped firstname.lastname@example.org will be delivered to email@example.com in case the catch-all feature has been activated for the latter. In this way, you can get email messages from partners or customers who may have sent a message to your email address with a spelling error or to an outdated one, which they may still have, but you have already deactivated. 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 begin receiving spam emails in the catch-all mailbox and the forwarding restriction implies that the spam will not be re-sent to a 3rd-party mailbox.