A catch-all mailbox receives email messages sent to non-existent addresses under the same domain. For example, an email message sent to the miswritten firstname.lastname@example.org will go to email@example.com in case the catch-all feature has been enabled for the latter. In this way, you can get messages from partners 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 deactivated. Just one single mailbox per domain name can be a catch-all one and email forwarding cannot be enabled 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 limitation means that the spam will not be re-sent to a 3rd-party mailbox.