A catch-all email mailbox receives messages sent to non-existent addresses under the very same domain. For instance, an email message sent to the misspelled 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messages from friends or clients who may have sent a message to your email address with a typographical error or to an outdated one, which they may still have, but you have already disabled. Just one single 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 a certain moment you may start receiving spam emails in the catch-all mailbox and the forwarding limitation means that the spam will not be received in a third-party mailbox.