A catch-all mailbox receives email messages sent to nonexistent email addresses under the exact same domain name. For instance, a message sent to the misspelled suport@domain.com will be delivered to support@domain.com if the catch-all feature has been enabled for the latter. Thus, you can get emails from partners or clients who may have sent a message to your email address with a spelling mistake or to an obsolete one, which they may still have, but you have already deleted. Only one single 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 a certain moment you may start receiving spam messages in the catch-all mailbox and the forwarding limitation implies that the spam will not be received in a third-party mailbox.