A catch-all email mailbox receives email messages sent to invalid addresses under the exact same domain. For example, an email message sent to the miswritten email@example.com will be delivered to firstname.lastname@example.org in case the catch-all feature has been enabled for the latter. In this way, you can receive email messages from colleagues or clients who may have sent a message to your email address with a typo or to an obsolete one, which they may still have, but you have already deleted. Only one mailbox per domain name can be a catch-all one and email forwarding cannot be set up for such a mailbox. This is due to the fact that at some moment you may start receiving spam messages in the catch-all mailbox and the forwarding restriction means that the spam will not be received in a third-party mailbox.