A catch-all email mailbox receives email messages sent to non-existent email addresses under the same domain. For example, an email message sent to the miswritten firstname.lastname@example.org will go to email@example.com if the catch-all feature has been enabled for the latter. Thus, you can get messages from pals or clients who may have sent a message to your email address with a spelling mistake or to an out-of-date one, which they may still have, but you have already disabled. Just one mailbox per domain can be a catch-all one and email forwarding cannot be activated for such a mailbox. This is so because of the fact that at some moment you may start receiving spam emails in the catch-all mailbox and the forwarding limitation implies that the spam will not be delivered to a third-party mailbox.