A catch-all email mailbox is one that captures all the messages sent to inactive addresses. For example, if your email address is firstname.lastname@example.org, but somebody mistypes it and sends a message to email@example.com, it will still be received in the catch-all mailbox that you have configured. Just one single mailbox per domain can have this feature enabled and thus you’ll never miss emails because the other side has an out-of-date email address or has made a spelling mistake. The disadvantage of having a catch-all mailbox is that you may begin receiving a lot of spam messages, but this problem can be fixed using anti-spam protection software. It’s also essential to remember that a mailbox with an active catch-all feature cannot forward inbound messages to a 3rd-party mailbox.