A catch-all email mailbox receives emails sent to non-existent email addresses under the very same domain. For instance, a message sent to the misspelled firstname.lastname@example.org will be delivered to email@example.com if the catch-all feature has been enabled for the latter. Thus, you can get emails from acquaintances or customers who may have sent a message to your email address with a typographical error or to an obsolete one, which they may still have, but you have already disabled. Just one mailbox per domain name can be a catch-all one and email forwarding cannot be activated for such a mailbox. This is due to the fact that at a certain point you may start receiving spam emails in the catch-all mailbox and the forwarding restriction means that the spam will not be received in a third-party mailbox.