A catch-all email mailbox receives messages sent to inactive email addresses under the exact same domain name. For instance, an email sent to the miswritten suport@domain.com will be delivered to support@domain.com if the catch-all feature has been activated for the latter. In this way, you can get emails from colleagues or clients who may have sent a message to your email address with a spelling mistake or to an old one, which they may still have, but you have already deleted. Just one single mailbox per domain name can be a catch-all one and email forwarding cannot be activated for such a mailbox. The latter is due to the fact that at a certain point you may start receiving spam email messages in the catch-all mailbox and the forwarding limitation means that the spam will not be delivered to a 3rd-party mailbox.