A catch-all email mailbox receives email messages sent to non-existent addresses under the very same domain name. For example, a message sent to the mistyped suport@domain.com will go to support@domain.com if the catch-all feature has been enabled for the latter. In this way, you can get emails from acquaintances or customers who may have sent a message to your email address with a spelling error or to an outdated one, which they may still have, but you have already disabled. Only one mailbox per domain 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 some moment you may begin receiving spam emails in the catch-all mailbox and the forwarding limitation implies that the spam will not be sent to a 3rd-party mailbox.